Saturday, 12 May 2018

What Makes a Normal Distribution Normal?

Good question...
What makes 98.60 degrees normal?
What makes people normal?

Generally, references to a statistical distribution or just a "distribution" mean a "frequency distribution." That is, what is the number of times or the frequency with which each value in the distribution occurs.

As it turns out, a large percent of all frequency distributions meet the same set of criteria. Such distributions are called "normal." A more popular term is "bell curve."

NOTE: "Bell" is not a technical term. However, because the term stuck, for convenience it is used in this series.

These normal types of distributions have many uses in market research and other statistical applications. A lot of statistical theory that applies to market research assumes normal distributions.

Examples of normal distributions in humans include: height; weight; test scores especially for standardized tests such as I.Q.; and various abilities, traits, tastes, and preferences. All assume a large number of people being "measured." One notable exception is income earned, which will be discussed in the next article with distributions that are not normal.

Normal distributions also are common in both nature and business. For example, light bulb packages have information on the number of hours the bulb should last, the watts (energy used), and the lumens (light output).

Each of those numbers is an arithmetic mean of the frequency distribution generated by testing large numbers of light bulbs. Each of those distributions is bell-shaped or normal.

So what are the criteria for a distribution to be normal?

1) The distribution is unimodal (only one most frequently occurring value).
2) The arithmetic mean, the mode, and the median are all the same value. That value is the value representing the highest point on the distribution;
3) The distribution is bi-laterally symmetrical.
Bi-laterally symmetrical means the left half is a mirror image of the right half (unless you're left-handed, then the right half is a mirror image of the left half).
4) One standard deviation--hereafter noted as 1�OE --measured each way from the arithmetic mean (what's referred to as plus or minus one standard deviation or � 1�OE) represents slightly over 68 percent of all the values in the distribution. � 1.96 �OEs represents the middle 95 percent of the values. You can go to readily available tables to see how many standard deviations from the mean are associated with what percent of all the values in the distribution. This percent is often referred to as the "area under the curve." For instance, � 1�OE covers slightly over 68 percent of the area under the curve. The curve is the graphic representation of the frequency distribution.
5) There are some other criteria, but the above ones are the main ones (at least for now).

Normal distributions come in various sizes and shapes but all meet the criteria noted above. Some normal distributions look like they are relatively short and spread out; other normal distributions look relatively tall and thin. The largest percent of all normal distributions are in between those more extreme shapes and are the true bell curves.

In market research, you might want to ask consumers how they would rate the service they received. A properly designed survey would gives choices such as "excellent" "good" "fair" "poor" "very poor." A future article will deal with the problems of such surveys. The point here is that the choices have to be symmetrical in terms of balancing the choices around the middle of the distribution. The results should produce a normal distribution. If the results are not "normally distributed" you should be suspicious of the results. Contrary to what many are led to think, not everything is good or excellent.

Friday, 11 May 2018

Modern Computer Networking

       Computer networking is the connecting of two or more computers that allows them to share resources. It can be done between computers in a home, in a business, across a corporation, and even internationally. It can equally be defined as a method of connecting two or more computer systems together including printers and other devices.

The benefits of networking are considerable, even on a network of only three systems. In computer networking there was never a truer statement than that this is a case of advantages experienced being far greater than the sum of the parts. PC networking is, as a consequence, a rapidly evolving discipline with many exciting opportunities. Challenges that arise in networking and particularly in the Internet tend to be truly global and have the potential to impact upon millions of users.

One huge and growing impact is Internet shopping. Shopping online has grown over the last 10 years to become a huge market, and if a sales business does not today incorporate this technology use they will fall behind their competitors.

But computer networking is also producing much more subtle uses within our societies. For example, Internet technologies can be deployed to favorably condition empathic response in those who have offended against community norms out of a lack of appreciation for the effects that their criminal behavior has on other people. In other words Internet linked devices can track home prisoners to maintain their behavior, in ways that 20 years ago had not even entered the heads of science-fiction writers, to the benefit of society as a whole.

Wireless Internet technology, is the development, also known as WiFi, which is really taking over the way people access the Internet and it has become widely popular in a very short space of time. One reason for this is it allows individuals to access the Internet via a network hot spots, while traveling without the use of cables or wires. In short it releases us from the tyranny of wires and plugs!

Wireless networks are now widely used including Internet-enabled mobile phones with cellular phone networks and, within buildings, wireless networks such as Bluetooth. These are in addition to the site networks used by academic institutions and large businesses. Wireless routers must be configured immediately for security right after you set up your network. It is important to emphasis that wireless can easily also mean insecure unless users are careful to set systems up correctly.

So, do this right away, as soon as you have got the device running. You need to set a new password for the router and limit access to only those computers on your wireless network.

Informally defined computer networking is the foundation of the Internet. The Internet itself is easier to understand when defined as the set of users, enterprises,and content providers that are interconnected by Internet Service Providers (ISP).

From an engineering standpoint, and please forgive me for being rather techie here; the Internet is the set of subnets, and aggregates of subnets, which share the registered IP address space and exchange information about the reachability of those IP addresses using the Border Gateway Protocol . Computer networks may also be classified according to the network layer at which they operate according to some basic reference models that are considered to be standards in the industry such as the seven layer OSI reference model and the five layer TCP/IP model.

Companies that use their own computer networks must administer complex systems which, once deployed, become vital tools for the continued efficiency of their operations. They employ administrators who focus primarily on the day-to-day operation of networks, while network engineers deal primarily with system upgrades, security testing, and so on.

Given the highly technological nature of computer networks you would have thought that just maintaining and developing these would be hard enough. However, companies also routinely face ongoing challenges with the fight against damaging software, such as malware such as worms, viruses, and spyware.

Computer networking has enabled people to work on the move, and take work home much more efficiently than has ever been possible before. Today's mobile workforce attach numerous devices to the corporate network that are hard to control from a security policy perspective. It is a common strand that companies that maximize the use of and benefits from the capacities and capabilities of their networks are able to gather, analyze, and disseminate critical marketing information quickly, which can give them an advantage over their competitors.

Friday, 4 May 2018


The following agricultural or farming practices carried out by farmers having some effect or consequence on the ecological system. These agricultural practices and their effect.
Bush burning: Involves the setting of fire on the bush to clear out the vegetation.
Effect of bush burning
1.     Burning of bush destroy the organic matter in the soil.
2.     The atmosphere is polluted with smoke.
3.     It exposes the soil to erosion and reaching.
4.     It releases minerals like potassium and phosphate to the soil in the farm of ash.
5.     Many of the micro-organisms are killed.
6.     The ash produced by bush burning gives the soil a slightly alkaline nature.
7.     It renews the growth of dried up grasses i.e. it encourages sprouting.
8.     Bush burning leads to the extinction of some animals.
9.     It helps to break dormancy of some seed.
1.     It reduces the water holding capacity of the soil.
Clean or bush clearing: Bush clearing is the practice where by the whole vegetation is cleared and removed; thus leaving the land clean.
Effect of bush cleaning
1.     Bush clearing result in the disturbance or removal of the rich top soil.
2.     It exposes the soil to direct sunshine; hence it affects evaporation of water.
3.     Bush clearing increases the temperature of the soil.
4.     It exposes the soil to erosion and increase leaching.
5.      Bush clearing lead to reduction of soil organism.
6.     It gets rid of weed on the land.
7.     It may leave the land free of all obstacles.
8.     It leads to reduction of organism matter content of the soil.



Pest are organism capable of causing damage to crops, food, livestock, etc.

Types of pest
1.    Insects.
2.    Birds.
3.    Rodent.
4.    Monkeys.
5.    Nematodes.
6.    Man.

Effect of economic importance of insect pest in crop production.
1.    Insect pest destroy crop in the field through their biting, chewing, boring, sucking and defoliation activities.
2.    They cause reduction in the viability of stored produces
3.    They increase the cost of production during the course of controlling them.
4.    They render vegetables fruit unattractive and unmarkable.
5.    They generally reduce the yield of crops.
6.    They reduce the quality of production either in the store or in the field.
7.    Some are carriers or vector of diseases.
8.     The profits of farmers are reduced.

Prevention and control of pest
          Pest of crops can be prevented or controlled through the following method.
1.     Physical control
2.     Cultural control
3.     Biological control
4.     Chemical control

·        Physical control: It involves the physical removal of a pest by:
1.     Hand picking of insect.
2.     Setting trap to catch rodent.
3.     Shooting rodent with gun.
4.     Tending around the rain with wire nets.

·        Cultural control: This method involves the use of farm activities to prevent or control pests especially on the field. Example of cultural control includes:
1.     Crop rotation.
2.     Bush fallowing.
3.     Change in the time or planting.
4.     Regular weeding.
5.     Proper timing or planting.
6.     Bush burning.
7.     Proper time or harvesting.

·        Biological control: It involves the introduction or the natural enemies. Such enemies eat up or feed on the pest.

·        Chemical control: It involves the use of chemicals called pesticides to control pest on crop plant. These chemical which are in form of powder, liquid, granules and tablet are used on the insect by various method like spraying or dusting seeds on plant to check pests. Examples of such chemical include:

1.     Insecticides
2.     Rodenticides
3.     Phosphate.
4.     Nematocides
5.     Pesticides. Etc.

Tuesday, 24 April 2018


Raising agent leaving agent are substance that produce gas in flour mixtures which cause them to rise and become lighter, bigger and softer in texture and forous after cooking. Raising agents are used generally in banking and frying products like cakes, pastries bread, puff-puff etc.

Types of raising agent
1.     Air
2.     Baking powder
3.     Cream of tartar or bicarbonate of soda
4.     Yeast
5.     Palm wine
6.     Steam
7.     Over-ripe bananas
8.     Sour milk
9.     Action of carbon dioxide in generating dough
10.                        Vinegar and bicarbonate of soda

1.     Air: Air beaten into egg while in the principal raising agent of omelets sponge cake.  When air is incorporated Into flour mixture and  put into the oven to bake trapped air expands in volume and therefore raises the products e.g. rich cake
2.     Palm wine: This acts as a raising agent because it contains yeast which products the raising effect condition needed for the growth of palm wine are warmth, sugar and moisture. It is used for making bread of different types.
3.     Sour milk: Used with bicarbonate of soda acts as a raising agent. The proportion are:
2tablespoon bicarbonate of soda to 1cup
Sour milk = 2tablespoon baking powder.
The raising agent is good for making ginger bread
4.     Over-ripe banana: Over ripe banana are used as a raising agent with the same characterizes in yeast. The over ripe banana are left to ferment before they are used. It is used for making breading large sealed.

Tuesday, 17 April 2018


Flour mixtures are products produce from flour with the addition of other ingredients. Flour mixtures can be grouped into the following.
  •  Cake
  • Pastry
  • Biscuits
  • Scones
  • Bread
  • Butter

The basic ingredients in the preparation and serving of flour mixtures are flour, fat, sugar, liquid flavouring and seasoning.
1.     FLOUR: Provide the structure for bake products in pastry or dough by the gluten (protein) in the flour.
2.     Fat or shortening: Fats add flavor to baked product, shorten them and make the products tender light and smooth e.g butter, margarine, cooking oil.
3.     Sugar: Sweetens the mixture improves the texture, develops colour and crispress and acts as food for yeast.
4.     Egg: Are used for leavening colouring shortening, nutritive value and strength.
5.     Liquid: Helps to bind the ingredients gelatinizes solve of the stand and develops the gluten e.g. milk, water, fruit juices.
6.     Flavouring and seasoning: Salt is the most important seasoning used in flour mixture. It helps to develop the flavour of the produce and helps to set the gluten. Other favour  used in  flour mixtures and seeds, nuts fruit juices, honey.

Career in food and nutrition

Through the study of food and nutrition so many opportunities are opened to the nutrition for example, nutrition can be employed in the teaching profession. The major causes of nutrition is ignorance about the science of mal-nutrition, the only competent person to impact this knowledge are the mal-nutritionist such person can be employed in schools where the subject is though under the umbrella of HOME ECONOMICS in schools of NURSING AND HEALTH TECHNOLOGY and the MEDICAL SCHOOLS.
Nutritionist can also be employed in the hospitals as dicticious: They will be responsible for the nutritional counseling of the patients who need dict therapy.
There are many nutritional diseases that need to be investigated. This is an aspect after referred to as clinical nutrition, and nutritionists can also be employed in such research area, the problem of food shortage cannot be4 solved without attention to adequate good storage and processing these areas comes under food science, food technology, and food engineering. Nutritionists can also be involved in these areas and another area that can be explored by the nutritionist is the food service and management.
Through the training undergone nutritionist can set up catering services and be self employed. This is an area where many nutritionist can be found, the service of nutritionist are also required in the rural areas where they assist in enlightening the people working in this capacity are called community nutrition. They can also be employed as matron in some institution was they will be responsible for the planning of menus, for the student at higher institution. Nutritionist can be involved in food research and development through this they will help in discovery of new methods of utilizing our various food stuff. Thereby broadening the taste of the people, the various career opened to the nutritionist are summarized below.
  • ·        Teaching
  • ·        Health clinic
  • ·        Food science
  • ·        Food technology
  • ·        Diatotics
  • ·        Community nutrition
  • ·        Food resource and development
  • ·        Catering & services
  • ·        Matron
  • ·        Institution


      Vegetarians are those people who do not eat animal flesh of fish and mostly eats foods that come from plants, like grains, fruits, vegetables, and nuts. There are three types of vegetarian.
1.     LACTO-OVO-VEGETARIANS: These are people who do not eat the flesh of animal, fish or poultry, but take milk, milk products and eggs in addition to vegetable which they consume in generous amounts.
2.     LACTO-VEGETARIANS: These people do not eat the flesh of animals, fish, poultry or eggs. However they take milk, milk products together with vegetables.
3.     STRICT VEGETARIANS: These people are also known as VEGANS, they do not eat the flesh of animals, poultry and fish as well as all the animal or dairy products. They eat only vegetable i.e. plant foods.


Milk is a cream liquid formed by all female mammals use for feeding their young. Milk can be produced from cows, horses, goats, ewes, sheep’s, monkeys, dog’s e.t.c.; the most commonly used is cow milk. Milk is regarded as nature’s perfect food but this is only tone as for babies, the nutrients are not in the correct proportion for adults.
          The proportion of carbohydrates is low and it is also lacking in iron and vitamin C. Milk is extremely valuable in the diet of invalids and convalescent on the account of its food value. It is readily digested.

Nutritive value of milk

1.     Protein: The principal protein or major protein is casein others are albumen and globin
2.     Carbohydrate: This is present in the form of simple sugar called LACTOSE.
3.     Fat: It exists in the form of a very fine emulsim and it is easily digested.
4.     Mineral salt: It is rich in calcium for building bones and also phosphorus and the amount of iron is small.
5.     Vitamins: Fat soluble vitamins A & D are present vitamin B (thiamine) and B2 (Riboflavin) B12 and small quantity of vitamin C which can be destroyed easily if milk is boiled, pasteurized of left standing in sunlight.
6.     Water: Forms the largest proportion of milk other substances are either dissolute or help in suspension by the water.

     When milk enters the stomach is separates into solid (lots of casein and liquid due to the action of rennin) on the casein digestibility depends on the size of the dots forms, large dots make digestion difficult.

Ways of making milk more digestion
1.     Dilution:
a.     Water
b.     Lime juice
2.     Accretion:
a.     Soda water
3.     By eating with solid food or thick drink e.g. porridge.
4.     Boiled milk dots more slowly and giried a less dens dot than raw milk.

Types of milk
1.     Fresh whole milk: This is the milk that is obtained directly from the cow in which none of the nutrients have been removed.
2.     Skimmed milk: The fat content has been removed. It is therefore made predominately of protein, carbohydrates, mineral and vitamin.
3.     Evaporated milk: This is whole milk from which about 60% of the water content has been removed.
4.     Dried or powdered milk: Over 90% of the water content has been remove and it is then milled to powder form.
5.     Condense milk: This is evaporated milk to which a safe and suitable nutritive sweetener usually sugar has been added so it is sweeter and thicker than evaporated milk.
6.     Filled milk: This is a combination of skimmed milk and vegetable fat or water, non fat dry milk and vegetable fat.

1.     Evaporation
2.     Dehydration
3.     Sterilization
4.     Pasteurization