AP Stats-Ch 18-19 QUIZ

What happens to the sampling distribution when the sample size increases?

• More normal with a smaller standard deviation

• More normal with a larger standard deviation

• More skewed with a smaller standard deviation

• Stays the same shape as the distribution for the population

Assume that 32% of the population is nearsighted, what is the standard deviation for the sample proportion for a group of 100 new students?

• 0.0022

• 0.0032

• 0.0466

• 0.0566

Past records from a certain species of frogs indicate the adults should weigh an average of 118 grams with a standard deviation of 14 grams. What is the probability that the average weight for a group of 50 frogs is less than 116 grams? (Try not to round until the end of your calculation).

• 0.1562

• 0.4432

• 0.5568

• 0.8438

Tags

CCSS.HSS.ID.A.4

According to the candy company, 12% of the jelly beans in their packages are red. Suppose they are packaged at random in small bags of 50. If you were to calculate the proportion for lots of bags, should the Normal model be used for this sampling distribution?

• Yes, all the assumptions and conditions are met.

• No, the "independence assumption" is not met.

• No the "10% condition" is not met.

• No, the "success/failure condition" is not met.

Given that 36% of the population have a tattoo, which of the following are true for the sampling distribution with n = 40? Select all that are correct based on the 68-95-99.7 rule.

• About 68% of the sample proportions are expected to be between 0.324 and 0.476

• About 95% of the sample proportions are expected to be between 0.248 and 0.552

• A sample proportion of 0.50 would be unusual

• A sample proportion of 0.20 would be unusual

Tags

CCSS.HSS.IC.B.4

Which is true about a 95% confidence interval?

I. There is a 95% chance that the parameter is in the calculated interval.

II. We're 95% confident that the statistic lies in the interval.

III. The interval is narrower than a 98% confidence interval.

• I only

• II only

• III only

• I and II

Tags

CCSS.HSS.IC.B.4

[Fill in the blank] When calculating a confidence interval, you take the statistic  $\pm$  (critical value)( _______________).

Tags

CCSS.HSS.IC.B.4

If you wanted to decrease the margin of error without losing any confidence, what should you do?

• Decrease the confidence level

• Increase the confidence level

• Decrease the sample size

• Increase the sample size

Tags

CCSS.HSS.IC.B.4

An election poll is to be conducted. The campaign director wants to estimate the proportion of voters in a large city that plan to vote for a particular candidate. What is the smallest sample size needed in order to estimate the proportion of voters that plan to vote for the candidate with a margin of error of 3% with 95% confidence?

• 456

• 752

• 1068

• 1960

Tags

CCSS.HSS.IC.B.4

[Fill in the blank] A random sample of 60 people were asked whether they prefer to eat mashed potatoes with a fork or a spoon and 27 said "spoon". The 90% confidence interval for the true proportion in favor of using a spoon is ______. (Round your interval values to three decimal places).

Tags

CCSS.HSS.IC.B.4