Statistics 11.2

Find the cumulative area that corresponds to a z-score of -2.19.

• 0.0143

• 0.0183

• 0.9857

• 0.0287

Find the area under the standard normal curve to the left of z = - 0.99.

Find the area under the standard normal curve between z = 1.25 and z =-1.5.

• 0.0668

• 0.8276

• 0.8944

• 0.9612

Find the area of the indicated region under the standard normal curve.

• 0.1587

• 0.9987

• 0.8412

• 0.1574

Find the indicated area under the standard normal curve to the right of z =-0.355

The average speed of vehicles traveling on a stretch of highway is 67 miles per hour with a standard deviation of 3.5 miles per hour. A vehicle is selected at random. What is the probability that it is violating the 70 mile per hour speed limit? Assume the speeds are normally distributed.

A survey indicates that for each trip to the supermarket, a shopper spends an average of 45 minutes with a standard deviation of 12 minutes in the store. The lengths of time spent in the store are normally distributed and are represented by the variable x. A shopper enters the store. Find the probability that the shopper will be in the store more than 39 minutes.

Assume the random variable x is normally distributed with mean μ = 174 and standard deviation σ = 20. Find the probability for x being between 160 and 170.

• -0.1787

• 0.1787

• 0.3373

• -0.3373

Assume a member is selected at random from the population represented by the graph. Find the probability that the member selected at random is from the shaded area of the graph. Assume the variable x is normally distributed.

A survey was conducted to measure the heights of U.S. men. In the survey, respondents were grouped by age. In the 20–29 age group, the heights were normally distributed, with a mean of 69.9 inches and a standard deviation of 3.0 inches. A study participant is randomly selected. Find the probability that his height is more than 72 inches.