Hypothesis Tests Proportions

In a population of bats living in a certain region, 30 percent have a wingspan greater than 10 inches. In a random sample of 80 bats living outside of the region, 20 had a wingspan greater than 10 inches. Consider a one-sample -test to investigate whether there is evidence that the proportion of bats with a wingspan greater than 10 inches living outside the region is different from that of the bats living in the region. Which of the following is the correct test statistic?

When conducting a significance test for the difference in proportions, why do we pool the data when finding standard error?

• Because we like to swim

• Because we assume p1 = p2 in Ho

• Because the sample sizes are always equal

• To be safe and make sure we don't underestimate the standard error

• Because we don't the standard deviation.

Which of the following is an appropriate interpretation of a p-value?

• The probability of rejecting H₀, when we should have failed to reject H₀.

• The probability of failing to reject H₀, when we should have rejected H₀.

• Assuming H₀ is true, it is the probability of obtaining our sample statistic or a more extreme value.

• Assuming H₀ is NOT true, it is the probability of obtaining our sample statistic or a more extreme value.

The NCAA requires colleges to report the graduation rates of their athletes. One Big Ten university reported that the graduation rates for a specific year were 21 of 28 females athletes and 24 of 46 male athletes. Is there evidence that a smaller proportion of male athletes than of female athletes graduate?

• 1-sample t-test

• 1-sample t-test (mean difference)

• 2-sample t-test (difference in means)

• 2-proportion z-test

The best points statistic is

• 52

• 100

• 0.025

• 0.520

• 0.051

The SE of the distribution is:

• 52

• 100

• 0.025

• 0.520

• 0.051

The P-value is

• 0.95

• 0.05

• 0.025

• 2 way tests don't have p-values

• 0.520

The 95% confidence interval is:

• 0.042

• 0.620

• (0.042 , 0.620)

• (0.025 , 0.950 )

Identify the correct null hypothesis:

Is the proportion of babies born male different from 50%? In a sample of 200 babies, 96 were male. Test the claim using a level of significance of 1%.

• H₀: p = 0.50

• H₀: µ = 100

• H₀: p = 0.48

• H₀: µ = 96

What is the critical value (in a test about proportions) for a left-tailed test with α = 0.05 and n ≥ 30. 

• z₀ = -1.645

• z₀ = -2.33

• z₀ = -1.96

• z₀ = 2.58