Stats Final Review

It was found that in a sample of 90 teenage boys, 63 of them have received speeding tickets.  What is the 90% confidence interval of the true proportion of teenage boys who have received speeding tickets? 

• (0.62055, .77945)

• (0.591, 0.812)

• (0.584, 0.830)

• (0.615, 0.805)

A survey of 800 women shoppers found that 136 of them shop on impulse.  What is the 98% confidence interval for the true proportion of women shoppers who shop on impulse? 

• 0.148 < p < 0.192

• 0.136 < p < 0.204

• 0.144 < p < 0.196

• 0.139 < p < 0.201

In a crash test of 15 troopers, collision repair costs are found to have a distribution that is approximately normal, with a mean of $1800 and a standard deviation of $950. Construct a 99% confidence interval for the repair cost for the population.

• (1070, 2530)

• (1273, 2326)

• (1799, 1801)

• (1776, 1823)

The lifetime of a certain type of batter is known to be normally distributed with a standard deviation of 20 hours. A sample of 50 batteries had a mean lifetime of 120.1 hours. It is desired to construct a 99% confidence interval for the mean lifetime of this type of battery.

• (114.5, 125.6)

• (112.81, 127.39)

• (112.82, 127.38)

• (114.56, 125.64)

Choose the statistical question:

• What time did you wake up this morning?

• What time do 12th graders wake up each morning during the school week?

A used car dealer says that the mean price of a three-year-old sport utility vehicle (in good condition) is $20,000. You suspect this claim is incorrect and find that a random sample of 22 similar vehicles has a mean price of $20,640 and a standard deviation of $1990. Calculate the Standardized test statistic for the large sample mean.  Round to the nearest hundredth. 

An education researcher claims that 57% of college students work year-round. In a random sample of 300 college students, 175 say they work year-round.  Calculate the Standardized test statistic for the large sample mean.  Round to the nearest hundredth. 

A person travels by car.  They record their miles driven in a data table.  Calculate the linear regression equation of this data.

• y = 61.93x - 1.79

• y = -1.79x + 61.93

• y = 0.016x + 0.03

• y = 0.03x + 0.016

The linear regression equation is y = 61.93x - 1.79.  Use the equation to predict how far this person will travel after 10 hours of driving.

• 10 miles

• 617.5 miles

• 0.19 miles

• 500 miles

• A

• B

• C

• D

• E