Inference for Proportions

Front

What is the critical z-score for a 94% confidence interval?

Back

1.88

Front

What is the smallest sample size that guarantees a margin of error of at most 0.08 for a 95% confidence interval?

Back

175

Front

What does a 95% confidence level mean in the context of confidence intervals?

Back

We would expect about 95 of the 100 confidence intervals to contain the proportion of all citizens of the United States who are optimistic about the economy.

Front

What are the appropriate hypotheses for testing if more than 50% of households gave a charitable donation?

Back

Ho: p = 0.5 and Ha: p > 0.5

Front

What does it mean if a 90% confidence interval for the difference in proportions includes 0?

Back

The researcher cannot conclude that the proportion of iPod owners at the two events is different.

Front

Define 'margin of error' in the context of confidence intervals.

Back

The margin of error is the range of values above and below the sample proportion that is expected to contain the true population proportion.

Front

What is a confidence interval?

Back

A confidence interval is a range of values, derived from a data set, that is likely to contain the value of an unknown population parameter.

Front

What is the formula for calculating the margin of error for a proportion?

Back

ME = z * sqrt[(p̂(1-p̂))/n], where z is the z-score, p̂ is the sample proportion, and n is the sample size.

Front

What does p̂ represent in statistics?

Back

p̂ represents the sample proportion, which is the number of successes divided by the total number of trials in the sample.

Front

What is the significance of the z-score in confidence intervals?

Back

The z-score corresponds to the desired confidence level and determines the width of the confidence interval.