Statistics and Probability Answers

The average public elementary school has 468 students with a standard deviation of 87. If a random sample of 38 public elementary schools is selected, what is the probability that the number of students enrolled is between 445 and 485?

1. The average number of milligrams(mg) of cholesterol in a cup of a certain brand of ice cream is 660 Ng, the standard deviation is 35mg. 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 670mg?

Given x1 = 3, x2 = 4, x3 = 8, x4 = -2, y1 = -6, y2 = 1, y3 = 5 and y4 = 0, find the value of the following:

Bob wants to know the average GPA of FC students. He surveys 150 random students, and their average GPA is 2.3. Bob reports that the average GPA of FC students is 2.3.

1) The following data is obtained from a research

a) Find the best equation fitting this data by using regression analyses method

b) Find the correlation coefficient of the equation

c) Find the y value for the x=5.5

X Y

5 784

10 1043

15 1666

20 2478

25 4060

30 6069

1) The vegetables grown in a farm have a mean weight of 23.2 ounces with a standard deviation of 1.5 ounces. Assuming that the distribution of the weights of these vegetables has roughly the shape of a normal distribution, what percentage of the vegetable weight

a) Less than 17.1 ounces

b) More than 19.3 ounces

c) Anywhere from 18.7 to 21.3 ounces

2)In a pollution study of the air in a certain downtown area, an EPA technician obtained a mean of 4.55 microgram of suspended bezene soluble matter per cubic meter with a standart deviation of 0.72 microgram for a sample of size n=9. Assuming that the population sampled is normal,

a) Construct a 90% confidence interval for the mean of the population sampled;

b) What can the technician assert with 95% confidence about the maximum error if x (mean)=4.55 micrograms per cubic meter is used as an estimate of the mean of the population sampled? 

11. In a boys’ school, there are 45 students in grade 10. The height of the students was measured. The mean height of the students was 154 cm and the standard deviation was 2 cm. Alex’s height was 163 cm. Would his height be considered an outlier, if the height of the students were normally distributed? Explain your answer.

The latest M1 Macbook Air and Macbook Pro are available for sale at the Apple Store in Gulshan. 70% of the people who want to buy a new Macbook prefer the Macbook Air, while the rest prefer the Macbook Pro. Suppose 16 customers were randomly selected among those shopping for Macbooks on a specific day.What is the probability that the number of people who want a Macbook Air is more than two standard deviations away from the mean value?

A discrete uniform population consists of the values 0,1,2, and 3. Suppose you have a sample size of 2 without replacement, find population and sample mean, variance, and standard deviation.

A population with a size of 4 has a mean of 5.41 and a variance of 6.8. The sampling distribution has a sample size of 3 and all possible samples are drawn without replacements. Find the mean, variance, and standard deviation.