Questions with Complete Solutions - Hamro CSIT

Write short note on:
a) Central limit theorem.
b) Determination of required sample size to estimate population proportion.

Not Answered Statistics II Asked on 2081 Exam

Explain briefly the queuing theory. Customers arrive at a one-man barber shop according to Poisson process with mean inter arrival time of 12 minutes. Customer spends an average of 10 minutes in the barber’s chair. What is the expected number of customers in the barber shop in the queue?

Not Answered Statistics II Asked on 2081 Exam

A multiple regression equation yields the following results:

Source Sum of square Degree of freedom

Regression 740 2

Error 510 17

i) What is the total sample size?
ii) How many independent variables are being considered?
iii) Compute the coefficient of determination and interpret its value.
iv) Compute the standard error of estimate.
v) Test the hypothesis that the overall fit of the model is significant or not. Assume .

Not Answered Statistics II Asked on 2081 Exam

Discuss the concept of level of significance in hypothesis testing. A manufacturer of laptop provides a particular model in one of three colors. Of the first 100 laptops sold, it is noted that 80 were the first color. Can you conclude that more than two third of all the customers have a preference for the first color? Use 5% level of significance.

Not Answered Statistics II Asked on 2081 Exam

Explain the concept of multiple and partial correlation coefficients. Consider three variables , $X_{2}$ and $X_{3}$ . If

, and find and

Not Answered Statistics II Asked on 2081 Exam

The mean drying time of a brand of spray paint is known to be 122 seconds. The research division of the company that produces this paint contemplates that adding a new chemical ingredient to the paint accelerate the drying process. To investigate this conjecture, the paint with the chemical additions is sprayed on 50 surfaces and the drying time is recorded. The mean and standard deviation of drying time computed from these recorded are found as 116 seconds and 16.8 seconds respectively. Do these data provide strong evidence that the mean drying time is reduced by the addition of the new chemical? Use 5% level of significance. Also find p-value.

Not Answered Statistics II Asked on 2081 Exam

Define confidence level in estimation. A quality control inspector collected a random sample of 400 tubes of toothpaste from the production line and found that 20 of the tubes had leaks from the tail end. Construct 96% confidence interval for the percentage of all the toothpaste tubes that had leakage and interpret the result.

Not Answered Statistics II Asked on 2081 Exam

Based on interviews of couples seeking divorce, a social worker complies the following data related to the period of acquaintanceship before marriage and the duration of marriage:

Acquaintanceship before marriage Duration of marriage Total

Less than or equals to 5 years More than 5 years

Below 0.5 year 15 7 22

0.5 – 1.5 years 26 22 48

Over 1.5 years 19 11 30

Total 60 40 100

Perform a test to determine if the data substantiate an association between the duration of a marriage and the acquaintanceship prior to marriage. Use 5% level of significance.

Not Answered Statistics II Asked on 2081 Exam

Explain, stating clearly the assumptions involved in the t-test for testing the significance of difference between two sample means. Measurements of the left-and-right-hand gripping strengths of 8 left-handed writers are recorded:

Person 1 2 3 4 5 6 7 8

Left hand 112 131 142 90 125 130 95 90

Right hand 104 136 135 86 132 120 86 85

Do the data provide strong evidence that the people who write with left hand have greater gripping strength in the left hand than they do in the right hand? Use .

Not Answered Statistics II Asked on 2081 Exam

A management consulting company presents a 3-day seminar on project management to various clients. The seminar is basically the same each time it is given. However, sometimes it is presented to high-level managers, sometimes to mid-level managers, and sometimes to low-level managers. The seminar facilitators believe evaluations of the seminar may vary with the audience. Suppose the following data are some randomly selected evaluation scores from different levels of managers after they have attended the seminar. The ratings are on a scale from 1 to 100, with 100 being the highest score. Use a one-way ANOVA to determine whether there is a significant difference in the evaluation according to manager level. The following table gives the scores to the various clients due to different manager levels.

High Level Mid Level Low Level

85 90 55

75 100 75

85 95 80

60 85 75

70 90

75

Not Answered Statistics II Asked on 2081 Exam

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