Proportions
If the variability within two sampled populations is high, what impact does it have on the width of a confidence interval for the difference in population proportions?
It determines whether a confidence interval can be constructed.
It decreases the width of the confidence interval.
It increases the width of the confidence interval.
It has no effect on the width of the confidence interval.
Which of the following is a measure of center used to describe the middle value in a data set?
Median
Standard deviation
Range
Variance
If an AP Statistics student wants to assess whether there is evidence of a significant difference in support between two presidential candidates, what must they check about their random samples from each candidate's supporters?
They must ensure that both samples are independent and randomly selected from their respective populations.
Both samples need not only be large but also exactly equal in size for comparison purposes.
They should check if all individuals in both samples strongly support their candidate without any bias.
It is essential that both samples come from populations with the same standard deviation in opinions.
A survey was conducted to compare the proportion of students who prefer math and those who prefer literature. The 95% confidence interval for the difference in proportions is (-0.03, 0.15). What does this interval suggest?
The proportion of students who prefer literature is higher than the proportion who prefer math.
There is not enough information to draw any conclusions.
There is no evidence to support a difference in the proportions of students who prefer math and literature.
The proportion of students who prefer math is higher than the proportion who prefer literature.
Which term describes how spread out or clustered together the values in a data set are?
Mode
Mean
Variability
Median
Which condition must be checked before using normal approximation to create a confidence interval for the difference between two independent sample proportions?
There should be at least 30 successes and failures combined across both samples.
Sample sizes must be equal.
The samples must come from normally distributed populations.
Success-failure condition (np and nq should both be greater than or equal to 10)
A student constructs a confidence interval for the difference in proportions and finds (0.10, 0.30). What can be concluded at the 90% confidence level?
There is strong evidence to support a difference in the proportions.
The student made a calculation error and should redo the interval.
There is no evidence to support a difference in the proportions.
The sample size was too small to make any inference.

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A researcher constructs a confidence interval for the difference in proportions and finds (-0.01, 0.09). What can be concluded at the 95% confidence level?
There is no evidence to support a difference in the proportions.
The data collection method was flawed, leading to unreliable results.
The sample size was too small to make any inference.
The proportion of one group is significantly higher than the proportion of the other group.
What assumption do statisticians make regarding binomial settings when estimating a confidence interval for p̂1 - p̂2?
Each individual observation within each group must follow an identical binomial distribution pattern.
There needs to exist perfect symmetry between success and failure rates within each binomial setting sampled.
There should be at least ten successes and ten failures within each sample group ( and (1-p) \geq 10).
Trials within each group must depend on one another so that probabilities remain consistent across observations.
If you calculate two separate 90% confidence intervals for two population proportions and they do not overlap, what can be inferred?
There cannot be any common value between these two populations' proportions.
At least one of the confidence intervals has been calculated incorrectly.
There is evidence to suggest that there may be a difference between the two population proportions.
The larger proportion is definitely greater than twice the smaller one.