STATISTICS (STAT-101)

28 Aug STATISTICS (STAT-101)

Student Full Name:___________________________________ .

Student ID:__________________________________________ .

CRN No:____________________________________________ .

STATISTICS (STAT-101)	Day: Wednesday Date: 25.10.2017

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Total Points
True/False MCQ Short Answer	____/6 ____/6 ____/18
Total	____/30

Good Luck

STATISTICS (STAT-101)

Marks- 30

Answer all the Questions on the same question paper.

Section-I

State whether the following statements are True or False. ( 6 marks, 1 Mark Each )

1. A fair coin is tossed 6 times. The probability of it lands tails up exactly 3 times is 10× ( .

2. A frequency distribution groups data into classes showing the number of observations in each class.

3. If probability sampling is done, each item in the population has a chance of being chosen.

4. A critical value is a Z-score separating unlikely value from those that are likely to occur.

5. A point estimate is a single value or point used to approximate a population parameter.

6. The number of women taller than 68 inches in a random sample of 5 women is an example of continuous random variable.

Section-II

Mark the right answer from following multiple-choice questions:

(Multiple Choice Questions) (6 marks, 1 Mark Each)

1. A standard normal distribution has the mean equal—–and variance=——:

a. 0,1.

b. 1,0.

c. Either a or b.

d. None .

2. 10% of college students are left-handed. For a statistics class of 35 students, find the mean number of left-handed students.

a. 3.5

b. 3.15

c. 1.77

d. None of the above

3. If the sampling error (E) is allowed to increase, which of the following is true regarding the sample size?

a. The sample size will increase

b. The sample size will decrease

c. The sample size will stay the same

d. The sample size cannot be determined

4. If each of a set of raw scores is transformed into a Z-score, the new

        distribution will have a standard deviation equal to

a. zero.

        b. one.

        c. the mean of the original distribution.

        d. the standard deviation of the original distribution.

5. The t distribution has degrees of freedom.

a. n

b. 2

c. 10

d. n – 1

6. If the z – score of normal distribution is 1.7, the mean of the distribution is 25 and the standard deviation of normal distribution is 3 then the value of X for a normal distribution is

a. 0

b. 47.5

c. 52.5

d. 30.1

Part-II (Multiple Choice Questions) (6 marks, 1 Mark Each)

MCQ	1	2	3	4	5	6
Answers

Section –III

Answer the following Essay Type Questions (18 marks, 6 Mark Each)

Question 1 :

a. A bank vice president feels that each savings account customer has, on average, 3 credit cards. The following distribution represents the number of credit cards people own. Find the mean, variance, and standard deviation.

Number of cards x	0	1	2	3	4
Probability P(x)	0.18	0.44	0.27	0.080	0.03

b. The Bruskin Market Research, Inc. determined that 40% of college students work part-time during the academic year. For a random sample of 5 students, what is the probability that

1) at most 3 work part-time?

2) at least 2 work part-time?

3) fewer than 3 work part-time?

Question 2 :

a. Find

a) P(z < 2.0)

b)  P(z > -1.88)

c) P(-1.18 < z < 2.1).

b. Burger mania claims that the mean number of grams of fat, μ , in its cheese Burger is 24 grams with a standard deviation, σ, of 5 grams. If a sample of 50 cheese Burgers is taken, what is the probability that the sample mean is 26 grams or more ?

Question 3:

a- An automobile dealer wants to estimate the proportion of customers who still own the cars they purchased six years ago. A random sample of 200 customers selected from the automobile dealer’s records indicates that 88 still own cars that were purchased six years earlier. Construct a 95% confidence interval estimate of the population proportion of all customers who still own the cars they purchased six years ago

b- A sample of 40 country CD recordings of Willie Nelson has been examined. The average playing time of these recordings is 51.3 minutes, and the standard deviation is 5.8 minutes. Construct a 95% confidence interval for the mean playing time of all Willie Nelson recordings. (t = 2.0227 for 39 degree of freedom).

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