Statistics and Probability Answers

How many possible samples of size n = 3 can be drawn from a population of size 10?

Determine the area of the normal distribution with mean of 10, standard deviation of 5 and scores between 5 to 12

Assume that when adults with smartphones are randomly selected, 39% use them in meetings or classes. If 8 adult smartphone users are randomly selected, find the probability that exactly 5 of them use their smartphones in meetings or classes.

As the sample size n increases, the shape of the distribution of the sample means taken from a population with the mean and standard deviation will approach a normal distribution. This distribution will have a mean and standard error.

A. Sample mean

B. Central limit theorem

C. Sample size

D. Sampling distribution

determine the area of the region indicated 1.32<z<2.47

Consider the normal distribution of IQs with a mean of 100 and a standard deviation of 16. What percentage of IQs are

a. greater than 95?

b. less than 120

c. between 90 and 110

What's More

Let's see how well you understood our discussion. At this point, I want you to

solve the following problems. Show your complete solution by following the step-by-

step procedure.

1. The average number of milligrams (mg) of cholesterol in a cup of a certain brand

of ice cream is 660 mg, the standard deviation is 35 mg. Assume the variable is

normally distributed.

a. If a cup of ice cream is selected, what is the probability that the cholesterol

content will be more than 670 mg?

b. If a sample of 10 cups of ice cream is selected, what is the probability that

the mean of the sample will be larger than 670 mg?

2. In a study of the life expectancy of 400 people in a certain geographic region, the

mean age at death was 70 years, and the standard deviation was 5.1 years. If a

sample of 50 people from this region is selected, what is the probability that the

mean life expectancy will be less than 68 years?

"An electrical firm produces light bulbs that have a length of life that is approximately normally distributed with a mean of 680 hours and a population standard deviation of 26 hours. A new version of light bulbs is being produced and is assumed to be better than the previous version. To test this claim, a random sample of 93 new light bulbs are tested. Would you agree with this claim if the random sample showed an average of 920 hours? Use a 0.1 level of significance.

What are the given? Write only the number. :

population mean: Blank 1 hours

population standard deviation: Blank 2 hours

sample size: Blank 3

sample mean: Blank 4 hours

level of significance: Blank 5

What is the critical value?

z: Blank 6

What is the value of the calculated z? Round your answer to the nearest hundredths.

z: Blank 7"

let x be a binomial random variable. use the formula to compute the following probabilities;

(a) p(x=2), if n=8 and p=0.1

(b) p(x=5), if n=9 and p=0.5

(c) p(x=9), if n=10 and p=0.95