STATISTICAL FUN FACTS

• Worldwide, around 265 people are born every minute and 115 people die, for a net increase in population of 150 people every minute.

• Only 1% of the population has a "genius" IQ, one of 140 or higher.

• Over 88% of the world's population lives north of the Equator.

• In 1915, statistics were compiled from 18 U.S. states of the number of deaths from three branches of outdoor sport. 16 people were killed in football, 59 in hunting, and 59 in baseball.

• According to a study by Swiss researchers, people are 14% more likely to die on their birthday than on any other day of the year.

• 100 people a year choke to death on ball-point pens.

G.K. Elio

STATISTICAL FUN FACTS

 60,000 plastic bags are used in the U.S every 5 seconds.

106,000 alliminum cans are used in the U.S every 30 seconds.

1.14 million paper bags are used in U.S supermarkets every hour.

One in 4 people over 60 has lost all there teeth.  

 

Over 2,500 left handed people are killed per year, from using products made for right handed people.

 

A person uses about 57 sheets of toilet paper per day.

 

There are over 9,700 juveniles in prisons across the United States.  

 

1.5 Million Americans are charged with drunk driving per year.

 

About 200,000 people die from cigarette smoking every 6 months.

 

It's estimated that at any given time 7% of the worlds population is drunk.

Only one person in two billion will live to be 116 or older.

G.K. Elio

Z-test for Difference of Proportions
              -used to test the hypothesis that two populations have the same proportion.


              For example suppose one is interested to test if there is any significant difference in the habit of tea drinking of male and female citizens of a town. In such situations, Z-test for difference of proportions can be applied.
              One would have to obtain two independent samples from the town- one from males and the other from females and determine the proportion o tea drinkers in each sample in order to perform this test.






POSTED BY: VON ERJUN SABUSAP

Statistics Facts
         Two in five people in the world marry their first love.


         There are more than 150 million sheep in Australia, and only some 20 million people.



Posted by: V.E. Sabusap

Decision Rule When using a P-Value
If P-value ≤ α, reject the null hypothesis.
If P-value >α, do not reject the null hypothesis.

When the population standard deviation is unknown and the sample size is less than 30, the z test is inappropriate for testing hypotheses involving means. A different test called the t test is used. The t test is used when σ is unknown and n<30.

t = x -μ over s/√n      d.f.=n-1

The formula for the t test is similar to the formula of the z test. But since the population standard deviation is unknown, the sample standard deviation is used instead.

Find the critical value for the following:

1. α = 0.05 with d.f = 16 for a right tailed test.
2. α = 0.01 with d.f = 22 for a left tailed test.
3. α = 0.10 with d.f = 18 for two tailed test.

Solution:

1. Find the 0.05 column in the top row and 16 in the left-hand column. Where the row and column meet, the appropriate critical value is found; +1.746.
2. -2.508 since the test is one-tailed test.
3. Find the 0.10 column in the row labeled "Two tails" and find 18 in the column labeled "d.f." The critical values are +1.734 and -1.734.

When testing hypotheses by using the t test (traditional method), follow the same procedure as to the z test, except use the Table F.


Posted by: V.E. Sabusap