Statistics and Probability Answers

2. A power company wants to see if the average amount of current passing through a series of connections is larger than 30 milliamperes (mA).

In words,

Ho: _______________________________________________ _______________________________________________

In symbols,

Ho: μ = 30

In words,

Ha: The average amount of current passing through a series of connections is larger than 30 milliamperes (mA).

In symbols,

Ha: ____________

One-tailed or directional test (specifically right-tailed)

ACTIVITY 6. INTRODUCTION TO HYPOTHESIS TESTING

A. Complete the tables by providing the necessary information.

1. The mean grade of a GAS student in a Statistics class is not 80.

In words,

Ho: The mean grade of a GAS student in a Statistics class is 80. In symbols,

Ho: ____________

In words,

Ha: _______________________________________________ _______________________________________________

In symbols, Ha: μ ≠ 80

Two-tailed or Non-directional test

A sample of 20 observations is selected from normal population distribution with

population standard deviation 9 and sample mean 51. Determine the highest

value of population mean with 95% confidence interval (z-1.96). Round the

answer to the two decimal places.

Determine the standard error if a population standard deviation is 31 and sample

size is 19. Round the answer to the two decimal place.

the IQ of 600 police applicants are normally distributed with a mean of 115 and standard deviation of 12. If the police academy requires at least IQ of 95, how many will be admitted?

A study found that 68% of the population owns a home in a random sample of 150 households 92 owned a home at the a=0.01 level is there enough evidence to reject the claim

1. A fruit juice franchise company has a policy of opening new fruit juice stand only on those areas that have a mean household income of at least ₱30,500 a month. The company is currently considering an area in which to open a new fruit juice stand. The company’s research department took a sample of 25 households from this area and found that the mean monthly income of these households is ₱32,600. Using 5% significance level, would you conclude that the company should open a fruit juice stand in the area? Also, find the 95% confidence interval of the true mean.

A consumer advocacy group suspects that a local supermarket’s 500 grams of sugar actually weigh less than 500 grams. The group look a random sample of 20 such packages, weigh each one, and found the mean weight for the sample to be 496 grams with standard deviation of 8 grams. Using 1% significance level, would you conclude that the mean weight is less than 500 grams? Also, find the 99% confidence interval of the true mean.

Solve the given problems.

1. A population consists of the four numbers 1, 2, 4 and 5. List all the possible

samples of size n = 2

which can be drawn with replacement from the population.

Find the following:

a. Population mean

b. Population variance

c. Population standard deviation.

d. Mean of the sampling distribution of sample means

e. Variance of the sampling distribution of sample means

f. Standard deviation of the sampling distribution of sample means

What is the normal probability distribution for P ( -0.21< z < 0.85)?