Statistics and Probability Answers

A computer store sells computer packages. Since the package is so expensive, the company wants to advertise an impressive guarantee on this hardware. The guarantee policy will replace the unit if the computer fails during the guaranteed period. The research department has done tests shows that the mean life for the computers is 36months, with standard deviation of 12months. The computer life is normally distributed. How long can the guarantee period be if the company does not want to replace the unit on more 8% of the computer package?

The students of a large university in Luzon were studied regarding their hours of sleep at night. The hours of sleep can be modeled as a normal distribution with mean of 6.9 hours and standard deviation of 1.5 hours. Find the 85th percentile of the distribution for hours of sleep.

consider that in a population of Filipino adults ages 18 to 65, Body Mass index (BMI) is normally distributed with mean of 28 and a standard deviation of 6.(A) what is the BMI marks the bottom 10%of the distribution for this population? (b) What BMI marks the bottom 10% of the distribution for this population?

For which of the following probability of distribution are the mean and variance equal? (a) Normal (b) Gamma (c) Poisson (d) Binomial

Two coins tossed simultaneously.A person receive Rs.8 each head and losses Rs.10 for each tail.Find expected value of the amount

All freshmen in a particular school were found to have variation in grades expressed as a standard deviation. Two samples among these freshmen, made up of 30 and 50 students each, were found to have means of 90 and 86 with a standard deviation of 2.75 and 1.50 , respectively. Based on their grades, is the first group really brighter than the second group at .05 level of significance? 

All freshmen in a particular school were found to have variation in grades expressed as a standard deviation. Two samples among these freshmen, made up of 30 and 50 students each, were found to have means of 90 and 86 with a standard deviation of 2.75 and 1.50 , respectively. Based on their grades, is the first group really brighter than the second group at .05 level of significance? 

Which is shorter, a 95% z-interval for the mean or a 95% t-interval for the mean? Is one of these always shorter, or does the outcome depend on the sample?

Determine the values of c so that the following functions represent joint probability distributions of the random variables X and Y : f(x, y) = c|x − y|, for x = −2, 0, 2; y = −2, 3.

A shopkeeper stock two brands of detergent A and B. Due to difficulty in the economy due to the covid - 19 pandemic, he decided that he want to only stock one brand of the two detergents. In order to make this decision, he consulted you a statistician to evaluate the average sales of the products in the last 4 months.

The shopkeeper is interested in knowing if product B has higher sales than A. During the period, product A was sold for 35 days while product B was sold for 40 days with the sales record for the days being available. State the best test statistic for the study