Statistics and Probability Answers

Americans ate an average of

25.7 pounds of confectionery products each last year

and spent an average of $61.50 per person doing so. If

the standard deviation for consumption is 3.75 pounds

and the standard deviation for the amount spent is

$5.89, find the following:

a. The probability that the sample mean confectionary

consumption for a random sample of 40 American

consumers was greater than 27 pounds

b. The probability that for a random sample of 50, the

sample mean for confectionary spending exceeded

$60.00

The number of road construction projects that take place at any one time in a certain city follows a Poisson distribution with a mean of 7. Find the probability that more than four road construction projects are currently taking place in the city

A random sample of 10 chocolate energy bars of a certain brand has, on average, 230 calories per bar, with a standard deviation of 15 calories. Construct a 99% confidence interval for the true mean calorie content of this brand of energy bar. Assume that the distribution of the calorie content is approximately normal.

The yield of a chemical process is being studied. From a previous experience yield is known to be normally distributed and σ = 3. The past 5 days if plant operation have to resulted in the following percent yields: 91.6,88.75,90.8,89.95, and 91.3. Find a 95% two-sided confidence interval on the true mean yield.

A random sample of 10 chocolate energy bars of a certain brand has, on average, 230 calories per bar, with a standard deviation of 15 calories. Construct a 99% confidence interval for the true mean calorie content of this brand of energy bar. Assume that the distribution of the calorie content is approximately normal.

A confidence interval estimate is desired for the gain in a circuit on a semiconductor device. Assume the gain is normally distributed with standard deviation σ = 20.

a) Find a 95% confidence interval for μ when n = 10 and x̄ = 1000.

b) Find a 95% confidence interval for μ when n = 25 and x̄ = 1000.

c) Find a 99% confidence interval for μ when n = 10 and x̄ = 1000.

d) Find a 99% confidence interval for μ when n = 25 and x̄ = 1000.

The width and height of the normal curve distribution is determined by the

Hammer It Out is a panel beater business in Silverton, Pretoria, that repairs cars that have been involved in accidents. It finds that it receives cars for repair at a rate of 3 per day.

Calculate the probability of Hammer It Out receiving 20 cars for repair during a random week (they operate 5 days a week).

the probability of observing defective item in a lot is 0.01.suppose 25 items are inspected from the lot,what is the probability that not more than 3 defective are found, exactly 4 defective are found.(max 1024)

A random sample of size 36 was taken from the population with a mean of 3.4 and a variance of 4. Approximately the probability that the sample mean is greater than 3.0 but less than 3.6