Stats Assignment 5 on Hypothesis Tests |

1/ The yield of alfalfa from 6 test plots is 1.4, 1.8, 1.1, 1.9, 2.2, and 1.2 tons per acre.

Test at the 5% level of significance whether this supports the claim that

the average yield for this kind of alfalfa is 1.5 tons per acre.

(5)

2/ In the comparison of 2 kinds of paint, a consumer-testing service found that

4 one-gallon cans of brand A covered an average of 514 sq. ft. with a standard deviation

of 32 sq. ft., while 4 one-gallon cans of brand B paint covered an average of 487 sq. ft.

with a standard deviation of 27 sq. ft.

Use the 5% level of significance to test whether the difference between the

two sample means is significant.

(5)

3/ The following data were obtained in an experiment designed to check whether

there is a difference in the weights (grams) obtained with two different scales:

__
__

__SPECIMEN____SCALE 1____SCALE 2__
1
12.13
12.17
2
17.56
17.61
3
9.33
9.35
4
11.4
11.42
5
28.62
28.61
6
10.25
10.27
7
23.37
23.42
8
16.27
16.26
9
12.4
12.45
10
24.78
24.75 __
__

Use the 1% level of significance to test whether the __difference__ between

the means of the weights obtained with the two scales is significant.

(5)

4/ Samples of 50 freshmen from two Universities were given a special test

to determine their knowledge of history. The average score from University A

was 67.4 with a standard deviation of 5. The average score from university B was 62.8

with a standard deviation of 4.6.

Test at the 5% level of significance whether the difference between

the two samples is significant.

(5)

5/ To test the effectiveness of a new drug, 80 patients at a clinic were given the drug

and 80 others were given a placebo. If 56 of the patients who received the drug

and 38 of those who received the placebo felt a beneficial effect, what can we

conclude at the 1% level of significance about the effectiveness of the new drug?

(5)

6/ The student newspaper interviewed a random sample of 200 male students and

found that 150 were in favor of having a homecoming dance.

A random sample of 400 females revealed that 312 were in favor of the dance.

At the 10% significance level, does the sample evidence show that there is a

difference between the __proportion__ of males and females favoring a dance?

(5)

7/ A traffic engineer is studying the traffic pattern on a four-lane inbound expressway.

For an hour, he counts the number of vehicles using each of the four lanes.

The results are as follows:

__
__

__LANE____VEHICLES__
1
100
2
80
3
60
4
60 __
__

At the 5% significance level, test the hypothesis that traffic uses all four lanes equally.

(5)

8/ Studies have shown that in the past, 25.2% of the used cars bought in a particular

city are subcompacts, 52.9% are mid-sized and 21.9% are full-sized cars.

A sample of 500 sales during the first quarter revealed that 129 were subcompacts,

258 were mid-sized and 113 were full-sized cars.

Test at the 5% level of significance that there has been no change in the buying

habits with respect to used cars in that city.

(5)

9/ The table shows the results of a study in which independent random samples of

workers in 3 parts of the country were asked whether they feel that unemployment

or inflation is a more serious problem:

northeast
midwest
southwest
total
unemployment
87
73
66
226
inflation
113
77
84
274
total
200
150
150
500

Test at the 5% level of significance whether the differences among the sample __proportions__

of workers who chose unemployment are significant.

(5)

TOTAL (45)

.

Back to Statistics MathRoom Index

.