Unit 5 Review (BVD Stats)

The 90% interval for a statistics test was given by 72% ± 7%. What is the lower bound for the interval?

• 7%
• 72%
• 65%
• 79%

Tags

CCSS.HSS.IC.B.4

Which of the following changes to a study would result in a narrower confidence interval?

• increasing the confidence level, increasing the sample size
• decreasing the confidence level, decreasing the sample size
• increasing the confidence level, decreasing the sample size
• decreasing the confidence level, increasing the sample size.

Tags

CCSS.HSS.IC.B.4

A fitness company wishes to estimate the proportion of members who do yoga. They want to estimate with a margin of error of 0.03 and they want a 95% level of confidence. Previous data suggests that 20% of gym goers do yoga. Which of the following is the smallest sample size that meets these criteria?

• 460
• 494
• 293
• 180

Tags

CCSS.HSS.IC.B.4

A 90% confidence interval for a population proportion is determined to be 40% to 50%. If the confidence is increased to 95% confidence while the sample statistics and sample size remain the same, the confidence interval

• becomes wider
• becomes narrower
• does not change

Tags

CCSS.HSS.IC.B.4

A researcher wishes to estimate the proportion of Americans who have visited a theme park within the last five years.  He wishes to do this with 95% confidence with a margin of error of 0.05 or less. Which of the following is the smallest size that he could use?

• 40
• 212
• 324
• 385

Tags

CCSS.HSS.IC.B.4

You plan do construct a 92% confidence interval.  What critical value (z*) should you use?

• -.25
• -.40
• .04
• 1.75

You take a poll and find that 34% of the 100 people you asked dislike school lunches.  What is the standard error?

• 0.093
• 0.047
• .034
• .34

You take a random sample of freshmen and calculate the proportion that have been bullied at some point this year. Of the 290 freshmen, 105 said "yes". Calculate a 90% confidence interval for the true proportion.

• (36.2%, 46.2%)
• (31.85%, 48.15%)
• (31.57%, 40.85%)

Tags

CCSS.HSS.IC.B.4

You take a random sample of freshmen and calculate the proportion that have been bullied at some point this year. Of the 290 freshmen, 105 said "yes". Last year, the national proportion of freshmen who were bullied was 0.35. Are kids meaner this year? What are the hypotheses for this test?

• Ho: p = 0.38                        Ha: p = 0.35
• Ho: p > 0.35                        Ha: p = 0.35
• Ho: p = 0.35                        Ha: p = 0.38
• Ho: p = 0.35                        Ha: p > 0.35

You perform a test of significance and I calculate a  
P-value of 0.06.  Which of the following α levels is this value statistically significant at?
I. α = 5%
II. α = 1%
III. α = 10%

• III only
• I only
• I and II
• I, II, and III