# statistics

posted by .

You are the owner of an auto repair service. History tells you it takes on average 45 minutes to complete a repair job. You have determined the standard deviation for a job is 6 minutes. A women comes into your shop and tells you she must leave her car for repair, and that she will be shopping at the mall across the street. She says she will be back no earlier than 38 minutes, but she absolutely must leave no later than 55 minutes to pick up her child from school. What is the probability her car will be repaired during the 38 to 55 minute timeframe?

Thanks!

• statistics -

Calculate Z scores for both values.

Z = (x-μ)/SD, where x = score, μ = mean, and SD = standard deviation.

In table on back of your statistics book called something like "areas under normal distribution," use Z scores to find areas between scores and mean. Add the two values.

I hope this helps. Thanks for asking.

## Respond to this Question

 First Name School Subject Your Answer

## Similar Questions

1. ### Probability

You are the owner of an auto repair service. History tells you it takes on average 45 minutes to complete a repair job. You have determined the standard deviation for a job is 6 minutes. A women comes into your shop and tells you she …
2. ### statistics

An appliance repair shop owner has fitted the quadratic trend equation ŷ = 90 + 0.9x + 3x² to a time series of annual repair orders, with y= the number of repair orders and x= 1 for 2000. Forecast the number of repair orders …
3. ### stats

An automobile repair shop has determined that the average service time on an automobile is 2 hours with a standard deviation of 32 minutes. A random sample of 64 out of 400 services is selected. What is the probability that this sample …
4. ### psy

Eric has computed that it takes an average (mean) of 17 minutes with a standard deviation of 3 minutes to drive from home, park the car, and walk to his job. One day it took Eric 21 minutes to get to work. You would use the formula …
5. ### statistics

An employer wants to estimate to set a time limit so that 75% of the employees will finish a job on time. Past history has shown that the time required to do the job is normally distributed and has a mean time of 26 minutes with a …
6. ### stat

An employer wants to set a time limit so that 75% of the employees will finish a job on time. Past history has shown that the time required to do the job is normally distributed and has a mean time of 26 minutes with a standard deviation …
7. ### statistics

Eric has computed that it takes an average (mean) of 17 minutes with a standard deviation of 3 minutes to drive from home, park the car, and walk to his job. One day it took Eric 21 minutes to get to work. You would use the formula …
8. ### Operations management

An appliance manufacturer wants to contract with a repair shop to handle authorized repairs. The company has an acceptable range of repair time from 50 minutes to 90 minutes. Two firms have submitted bids for the work. In the evaluation …
9. ### statistics

The time required by workers to complete an assembly job has a mean of 50 minutes and a standard deviation of 8 minutes. To spot check the workers' progress on a particular day, their supervisor intends to record the times 60 workers …
10. ### Statistics

A large television repair service claims that its average repair charge is \$124. Suspecting that the average charge is higher, a consumer group randomly choose a sample of 35 statements for tv repairs done by the repair service and …

More Similar Questions