Prob/Stats Quiz 7.4 - 7.5

In a recent survey of 150 homes, 54 had central air. Find p̂

• 0.36

• 0.64

• 2.88

• 54

In a recent survey of 150 homes, 54 had central air. Find q^

• 0.36

• 0.64

• 2.88

• 54

A sample of 200 had a sample proportion of 42% and a 99% confidence interval for the population. Find p̂

• 200

• 2.58

• 0.42

• 0.58

A sample of 200 had a sample proportion of 42% and a 99% confidence interval for the population. Find n

• 200

• 2.58

• 0.42

• 0.58

A sample of 200 had a sample proportion of 42% and a 99% confidence interval for the population. Find Z -score

• 200

• 2.58

• 0.42

• 0.58

A sample of 200 had a sample proportion of 42% and a 99% confidence interval for the population. Find q^

• 200

• 2.58

• 0.42

• 0.58

What value is NOT used in the confidence interval of the variance formula

• Z - score

• variance

• t - value

• X² right

A recent study of 80 workers found that 60% rode the bus to work. Find a 95% confidence interval of the proportion of all workers who rode the bus to work.

• 0.493 < p < 0.707

• 0.510 < p < 0.690

• 0.459 < p < 0.741

• 0.552 < p < 0.648

A survey found that 80% of brides are planning to marry in the summer. How large of a sample is needed to estimate the true proportion within 3% and a 95% confidence.

• 11

• 110

• 1184

• 683

A sample of 25 novels has a standard deviation of 9 pages. Find the 90% confidence interval of the population variance. X² right =36.415. X² left = 13.848

• 53.38 < σ² < 140.38

• 5.93 < σ² < 15.60

• 7.31 < σ² < 11.85

• 2.44 < σ² < 3.95