Statistics and Probability Answers

The Smith Trucking Company claims that the average weight of its delivery

trucks when fully loaded is 6000 pounds with a standard deviation of 120

pounds. 36 trucks are selected at random and their weights recorded.

Within what limits will the average weights of 90% of the 36 trucks lie?

a group of student got the following scores in an achievement test 9,12,15,18,21 and 24. consider samples of size 3 that can be drawn from this population.

The production manager of a large manufacturing company estimates that the mean age of his employees is 22.8 years. The treasurer of the firm needs a more accurate employee mean age figure in order to estimate the cost of an annuity benefit program being considered for employees. The treasurer takes a random sample of 70 workers and finds out that the mean age of the employees sampled is 26.2 years with a standard deviation of 4.6 years. At the 0.01 level of significance, what can the treasurer conclude about the accuracy of the production manager’s estimate?

Apopulation consist of 1,3,5,7,9 with sample size 2

1. The number of accidents in a production facility has a Poisson distribution with a mean of 2.7 per month. For a given month, what is the probability that there will be more than three (3) accidents?

1. The blood groups of 200 people are distributed as follows: 40 have type A blood, 75 have type B blood, 60 have type O blood, and 25 have type AB blood. If a person from any of the group is selected at random, what is the probability that this person has an O blood type? How about the AB blood type?

The Following are the heights of four students in centimeters. Suppose samples of size 2 ae taken from this population of four students.

cardo-125 cm

alyana-120cm

joaquin-130 cm

flora-110 cm​

a. How many samples are possible? List them and compute the mean of each sample?

b. Construct the sampling distribution of the sample means

c. Construct the histogram of the sampling distribution of the sample means

You have a bag of marbles. 5 yellow, 5, green, 5

purple, 5 black, and 5 red. What is the

probability of pulling out a purple marble,

replacing it, then pulling out a black marble?

5

6

7

a division wide aptitude test in mathematics was conducted to 1,000 pupils the mean of the test is 58 and the standard deviation is 12. find the z-value that corresponds to a score x = 70. draw the normal curve distribution. what is your conclusion regarding the scores of the pupils

3. A division wide aptitude test in Mathematics was conducted to 3 800 students. The mean of the test is 58 and the standard deviation is 14.

a. What is the score that divides the distribution into two such that 80% of the cases is below it.

b. What are the scores that bounds the middle 90% of the distribution.

c. How many scores are between 60 and 96?

d. How many students belong to the top 12% of the examinees?