# Need help with statistics please?

## Steve Asked: Need help with statistics please?

1.) A study of college football games shows that the number of holding penalties assessed has a mean of 2.3 penalties per game and a standard deviation of 0.8 penalties per game. What is the probability that, for a sample of 40 college games to be played next week, the mean number of holding penalties will be 2.5 penalties per game or more?

Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.

2.)Polychlorinated biphenyl (PCB) is among a group of organic pollutants found in a variety of products, such as coolants, insulating materials, and lubricants in electrical equipment. Disposal of items containing less than 50 parts per million (ppm) PCB is generally not regulated. A certain kind of small capacitor contains PCB with a mean of 47.8 ppm and a standard deviation of 8 ppm. The Environmental Protection Agency takes a random sample of 39 of these small capacitors, planning to regulate the disposal of such capacitors if the sample mean amount of PCB is 49.5 ppm or more. Find the probability that the disposal of such capacitors will be regulated.

Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.

3.)The mean salary offered to students who are graduating from Coastal State University this year is $24,275, with a standard deviation of $3,678. A random sample of 85 Coastal State students graduating this year has been selected. What is the probability that the mean salary offer for these 85 students is $20,000 or more?

Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.

4.)The producer of a weight-loss pill advertises that people who use the pill lose, after one week, an average (mean) of 1.75 pounds with a standard deviation of 1.05 pounds. In a recent study, a group of 45 people who used this pill were interviewed. The study revealed that these people lost a mean of 1.7 pounds after one week. If the producer's claim is correct, what is the probability that the mean weight loss after one week on this pill for a random sample of 45 individuals will be 1.7 pounds or more?

5.)The lifetime of a certain brand of electric light bulb is known to have a standard deviation of 47 hours. Suppose that a random sample of 80 bulbs of this brand has a mean lifetime of 491 hours. Find a 90% confidence interval for the true mean lifetime of all light bulbs of this brand. What is the lower limit of the 90% confidence interval? & What is the upper limit of the 90% confidence interval?

6.)A union of restaurant and foodservice workers would like to estimate the mean hourly wage,population mean, of foodservice workers in the U.S. The union will choose a random sample of wages and then estimate population mean using the mean of the sample. What is the minimum sample size needed in order for the union to be 95% confident that its estimate is within $0.40 of population mean? Suppose that the standard deviation of wages of foodservice workers in the U.S. is about $2.15.

Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements).

7.)Many college graduates who are employed full-time have longer than 40-hour work weeks. Suppose that we wish to estimate the mean number of hours,population mean, worked per week by college graduates employed full-time. We'll choose a random sample of college graduates employed full-time and use the mean of this sample to estimate population mean. Assuming that the standard deviation of the number of hours worked by college graduates is 6.00 hours per week, what is the minimum sample size needed in order for us to be 95% confident that our estimate is within 1.5 hours per week of population mean?

Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements).

8.)A corporation that maintains a large fleet of company cars for the use of its sales staff is interested in the mean distance driven monthly per sales person. The following table gives the monthly distances in miles driven by a random sample of 12 sales persons: 2595, 2201, 1888, 2384, 2626, 2546, 2449, 1941, 2458, 1956, 2658, 2398

Based on this sample, find a 90% confidence interval for the mean number of miles driven monthly by members of the sales staff, assuming that monthly driving distances are normally distributed. Calculate the upper and lower limit of the confidence level

## Answers:

**Math Answered:**

No one will help you if you just put up all your homework and then leave. Also, the work to point ratio is way off.

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- The lifetime of a certain brand of electric light bulb is known to have a standard deviation of hours Suppose that a random sample of bulbs of this brand has a mean lifetime of hours Find a confidence interval for the true mean lifetime of all light bulbs
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