Mixed Confidence Intervals Quiz

Use the z table or your calculator to find the critical value that corresponds to 92% confidence.

Use the t table to find the critical value.

96% confident, df = 10

Use the t table to find the critical value.

95% confident, sample size = 8

Choose the appropriate confidence interval for the situation:

A random sample of 30 movie theaters showed that the average price for a movie was $10 with a standard deviation of $1.20.

Compute a 90% confidence interval for the situation:

A random sample of 30 movie theaters showed that the average price for a movie was $10 with a standard deviation of $1.20.

Choose the appropriate confidence interval for the situation:

After watching a horror film, 34 out of 50 people reported problems getting to sleep.

Compute a 95% confidence interval:

After watching a horror film, 34 out of 50 people reported problems getting to sleep.

Compute a 98% confidence interval:

Last year, the times for Midlo soccer games were normally distributed with a standard deviation of 2.8 minutes. A random sample of 7 soccer games this year had an average length of 94 minutes.

Decide if the distribution is normal:

In a sample of 28 students, 85% said they like horror movies.

Decide if the distribution is normal:

SAT scores are normally distributed with a standard deviation of 180. A random sample of 28 Midlo students had an average score of 1120.