Question

) A sample of eight observations of variables x and y is shown below:

x 5 3 7 9 2 4 6 8
y 20 23 15 11 27 21 17 14


Find the value of coefficient of correlation, r.

a) - 0.991
b) 0.872
c) - 0.512
d) 0.942

2) In the past, young women drivers have maintained a better driving record than young men drivers. An insurance company is concerned with the driving record of its insured customers. Specifically, it conducts a test for the number of speeding tickets received during the past year by drivers between the ages of 18 and 25. Men Women
n1= 120 n2= 85
1= 1.2 2 = 0.4
s21 = 24.8 s22 = 10.6

A test for the equality of average number of tickets per driver for the two groups is desired.

Use = 0.01.

Calculate the p-value for this test.

A) 0.3395
B) 0.2015
C) 0.1646
D) 0.4561

3) A producer of a juice drink advertises that it contains 10% real fruit juices. A sample of 75 bottles of the drink is analyzed and the percent of real fruit juices is found to be 6.5%. If the true proportion is actually 0.10, what is the probability that the sample percent will be 6.5% or less?

a)0.7211
b)0.1562
c)0.5488
d)0.8325

4) One-way ANOVA is performed on three independent samples with: = 6, = 7, and = 8. The critical value obtained from the F-table for this test at the 2.5% level of significance equals:

a)3.55
b)39.45
c)4.56
d)29.45

5) We calculate the three-period moving average for a time series for all time periods except the:

A) first period
B) last period
C) first and last period
D) first and last two periods

Answer 1

a sample of 16 ATM transactions shows a mean transaction time of 67 seconds with a standard deviation of 12 seconds. State the hypothesis to test whether the mean transaction time exceeds 60 seconds?