The lifetime of a light bulb is normally distributed with an average life of 500 hours and a standard deviation of 100 hours.  If a company installs 5000 of these light bulbs, find the number of bulbs that can be expected to last between 500 hours and 675 hours.

The percent of fat calories that a person in America consumes each day is normally distributed with a mean of about 38 and a standard deviation of 10. Suppose that one individual is randomly chosen. Let X=percent of fat calories. Round all answers to 4 decimal places if where possible

The human population has a mean IQ score of µ = 100 and a standard deviation of σ = 15. Find the z-score of a stat student who has an IQ score of 131.  Round to 3 decimal places.

The heights of all women in the United States are known to be normally distributed with a mean of 63 inches and standard deviation of 3 inches. The U.S. Navy requires that fighter pilots have heights between 58 inches and 72 inches. Find the percentage of women in the United States that meet this height requirement. Round the solution to two decimal places, if necessary.

The scores on a test are normally distributed with a mean of 150 and a standard deviation of 30. Find the score that is 2 1/2 standard deviations above the mean.

In a city of 45,000 homes, a survey was taken to determine the number with Wi-Fi access. Of the 500 homes surveyed, 300 had Wi-Fi access. Estimate the number of homes in the city that have Wi-Fi access.

The average age of senators in the 108th Congress was 62 years. If the standard deviation was 12.5 years, find the z-scores corresponding to the oldest and youngest senators of age 86 and 46. Round z scores to two decimal places.

A California lake has been stocked with rainbow trout. These trout have an average length of 24 inches, with a standard deviation of 3 inches. Someone goes fishing and catches a trout that is 26.25 inches long. Express the length of this trout in standard units, relative to all the trout that were used to stock the lake. Choose the answer below that is closest.

A study compared the weight loss of people on a low-fat diet versus people on a low-carb diet. In a sample of 100 obese people on a low-fat diet the sample mean weight loss as 7.6 pounds with a standard deviation of 3.2 pounds. In another sample of 120 obese people on a low-carb diet the sample mean weight loss was 6.7 pounds with a standard deviation of 3.9 pounds. Write down all formulas and state the hypothesisa) Test the hypothesis, at the 5% level of significance, that there is a difference in the mean weightloss of using the 2 different diets.  b) What is the p-value?

A photoconductor film is manufactured at a nominal thickness of 25 mils. The product engineer wishes to increase the mean speed of the film, and believes that this can be achieved by reducing the thickness of the film to 20 mils. Eight samples of each film thickness are manufactured in a pilot production process, and the film speed (in microjoules per square inch) is measured. For the 25-mil film, the sample data result is = 1.15 and 81 = 0.11, while for the 20-mil film, the data yield 2 = 1.06 and 82 = 0.09. Note that an increase in film speed vould lower the value of the observation in microjoules per square inch. (a) Do the data support the claim that reducing the film thickness increases the mean speed of the film? Use a = 0.10 and assume that the two population variances are equal and the underlying population of film speed is normally distributed. What is the P-value for this test? Round your answer to three decimal places (e.g. 98.765). The data the claim that reducing the film…