Statistics and Probability Answers

a) Yield strengths of circular tubes with end cups are measured. The first yields (in KN) are as follows: 96, 102, 104, 108, 126, 128, 150 and 156.

i. Calculate the sample average.

ii. Calculate the sample standard deviation.


b) Tests of line voltages to street lights show a mean of 118.5 V and a population standard
deviation of 1.20 V. Determine the percentage of data between 116 V and 120 V.

c) An electronic assembly is subjected to a final functional test. Suppose that defects occur at random in these assemblies, and that these defects occur according to a Poisson distribution with parameter .

i. What is the probability that an assembly will have exactly one defect?
ii. What is the probability that an assembly will have one or more defects?
iii. Suppose that you improve the process so that the occurrence rate of defects is
reduced to . What effect will this have on the probability that an
assembly will have one or more defects?

When 2 dice 1 red and green are rolled there are 36 outcome. If both dice are fair the outcome are equally likely. Let E be the event that the sum of the numbers rolled is 7. What is the probability of 7 ?

a fair dice is thrown twice. what is the probability that a 2 was scored on the first throw and a 4 on the second throw?

When spinning a wheel of chance with 48 "slots", 1000 times, how many times would you predict the wheel would stop on slot number 1?

determine the number of 5 cards combination out of 52 cards if each selection of 5 cards has exactly one king

the month in which the year's highest temperature occurs in a city has probabilities of the ratio 1:3:6:8 for May, June, July and August, respectively. Find the probability that the highest temperature occurs in either May or June.

An elementary school has 1000 students, 200 of which are enrolled in an experimental program and 800 in a regular program. The mean EOG test score for the entire school was 79 and the mean for the experimental group was 83. What was the mean for the students in the regular program?

For the most recent year available, the mean annual cost to attend a private university in the United States was $20,132. Assume the distribution of annual costs follows the normal probability distribution and the standard deviation is $4,450.


Ninety percent of all students at private universities pay less than what amount? (Round z value to 2 decimal places and your final answer to the nearest whole number.)

Amount $

A coin is weighted so that P(H) =2/5 and P(T) = 1/8 is tossed. If heads appear then a number is selected at random from the numbers 1 to 9; If tails appear then the numbers are selected at random from the numbers 1-5. Find the probability that the number is even.

A club consists of four girls and six boys.
a. In how many ways can a committee of three people be chosen?
b. In how many ways can two boys and two girls be chosen to attend a competition?
c. In how many ways can three boys be chosen?
d. What is the probability that three boys will be chosen?