Statistics and Probability Answers

 A rowing team consists of four rowers who weigh 152, 156, 160 and 164 pounds. 

1. How many samples of size n=2 can be drawn from this population ?
2. Construct a table showing all possible samples, mean and probability of each sample.
3. Construct the sampling distribution ( probability distribution ) of the sample means.
4. Draw the histogram of the sampling distribution of the means

1. A political campaign manager wishes to survey a number of voters to estimate

the proportion of those who are in favor of his candidate. If a previous survey

shows that 55% of registered voters plans to vote for his candidate, what is the

minimum sample size required to make his surveys accurate with a 95%

confidence level and a margin of error of 2.5%?

The mean height of the grade nine students at a certain high school is 164 centimeters and the

standard deviation is 10 centimeters. Assuming the heights are normally distributed, what

percent of the heights is greater than 168 centimeters?

The following data are the heights of four students in centimeter; 110, 125, 120, and 130. Suppose sample size of 2 is to be taken from the population of four students. What will be the probability when the sample mean is 115?

An electrical company claims that an average life of bulbs it manufacturers is 1200 hours with a standard deviation of 250 hours. If a random sample of 100 bulbs is chosen, what is the probability of the sample mean will be:

a. Greater than 1150 hours?

b. Less than 1250 hours?

c. Betweem 1150 and 1250 hours?

5 10 15 20 25 30 35 40

illustrate the variance and standard deviation

Medical Literature tells us that our blood is mainly composed of red and white corpuscles and a normal human body average 7250/mm³ of white blood cell counts.If a sample of 15 individuals chosen at random from a certain place has an average of 4850/mm³ with a standard deviation of 2500/mm^3, would you say that the people in that place have low white blood cell counts?

A.Formulate the null and alternative hypothesis in sentence and in symbol.

B.Determine what test statistics to use.

C.Compute the test statistics.

Medical literature tells us that our blood is mainly composed of red and white blood cells corpuscles and a normal human body must average 7250/mm³ of white blood cell counts.If a sample of 15 individuals chosen at random from a certain place has an average of 4850/mm³ with a standard deviation of 2500/mm³, would you say that the people in that place have low white blood cell counts?

A.Formulate the null and alternative hypothesis in sentence and in symbol.

B.Determine what test statistics to use.

C.Compute the test statistics.

a researcher thinks that if expectant mothers use vitamin pills the birth weigth of the babies will increase

There are two students who get A,B, or c grade. Find the sample space, and the values for random variable of number of students getting A grade.