AP Statistics Unit 7

A polling company is considering three sampling procedures over a specific population. Which of the following would have greatest variability?

• 80 samples of size 20

• 50 samples of size 50

• 20 samples of size 80

A company has 500 employees and wants to evaluate a proportion using the distribution of sample proportions and normal curve. Under which circumstance will they be able to do this?

• n = 80, p = .2

• n = 40, p = .2

• n = 40, p = .9

• n = 30, p = .4

The average points scored in an NBA game is 220 with a standard deviation of 18. Determine the likelihood that a sample of 10 games would have a mean greater than 230.

• 0.0395

• 0.0817

• 0.2893

• Cannot be determined

The average points scored in an NBA game is 220 with a standard deviation of 18. Determine the likelihood that a random sample of 40 games would have a mean less than 225.

• Cannot be determined

• 0.9605

• 0.6094

• 0.8563

Bias is similar to ______ while variability is similar to _____.

• precision, accuracy

• accuracy, precision

• skewed curves, normal curves

• random samples, non-random samples

10% of people are left handed. If 800 people are randomly selected, find the likelihood that at least 12% of the sample is left handed.

• 0.0297

• 0.0106

• 0.0409

• 0.0816

10% of people are left handed. Of the following, what is the smallest sample size needed to be at least 90% sure that the sample proportion will be between 9% and 11%?

• 1500

• 2000

• 2500

• 3000

A specific brand of potato chips sells bags such that the weights are N(8,0.5). If the probability that a sample of n bags has an average weight over 8.2 ounces is 0.0548, what sample size was used?

• 4

• 16

• 36

• 64

Which of the following is the central limit theorem used for?

• The standard deviation of the distribution of sample means is found by dividing the population standard deviation by n.

• The distribution of sample means will be approximately normal if the sample size is at least 30.

• The distribution of sample proportions is approximately normal if both np and n(1 - p) are greater than or equal to 10.

• As sample size increases, variability decreases.

53.2% of applicants are accepted into UConn. In a sample of 100 UConn applicants, 45 of them were accepted. What is the parameter?

• All UConn applicants.

• The 100 applicants in the sample.

• 53.2% acceptance rate.

• 45% of accepted in sample.