statistics need in 2 hours or less

6.A grouped frequency distribution has a mean of 100 and a
standard deviation of 20. The class limits for one class are 15 and 25. What
are the standard normal z-statistics for the class limits?
-20.0 and
20.0.
-4.25 and
-3.75
-15.0 and
-5.0
3.75 and
4.25
7 A random sample of 32 companies was selected and asked for
their annual dividend rate in three different industries: utilities, banking,
and insurance. The ANOVA comparing the mean annual dividend rate among three
industries rejected the null hypothesis. The Mean Square Error (MSE) was 3.36.
The following table summarized the results:
Utilities Banking Insurance
Number sampled 10
10 12
Mean annual dividend
rate 22.11 15.4 22.2
When comparing the mean annual dividend rate for companies
in the utilities and insurance industries, the following 95% confidence
interval can be constructed:
0.09 ±
2.179 * 1.57
0.09 ±
2.045 * 0.78
0.09 ±
2.179 * 0.78
0.09 ±
2.045 * 1.57
8 A recent study focused on the number of times men and
women send a Twitter message in a day. The information is summarized below.
Sample Size Sample Mean Population
Standard
Deviation
Men 24
19 11
Women 38 38 22
At the .01 significance level, is there a difference in the
mean number of times men and women send a Twitter message in a day? What is the
p-value for this hypothesis test?
0.0750
0.0000
0.0250
0.7500
A sales manager for an advertising agency believes that
there is a relationship between the number of contacts that a sales person
makes and the amount of the sales dollars earned.
A regression analysis shows the following results:
Coefficients Standard Error t
Stat P-value
Intercept 4.799
6.530 0.735 0.500
Number of Contacts 2.280 0.155 14.710 0.000
ANOVA
df SS MS F Significance F
Regression 1.00
13,650.94 13,650.94 485.97 0.00
Residual 25.00
702.32 28.09
Total 26.00
14,353.26
formula32.mml
The 90% prediction interval for a particular person making
13 calls is
24.93,
43.95
7.37, 1.50
7.63, 16.50
7.37, 31.50
The claim that "40% of those persons who retired from
an industrial job before the age of 60 would return to work if a suitable job
was available" is to be investigated at the 0.02 significance level. If 74
out of the 200 workers sampled said they would return to work, what is our
decision?
Do not
reject the null hypothesis because -0.879 lies in the region between +2.5760
and -2.576.
Do not reject
the null hypothesis because 37% lies in the area between 0% and 40%.
Do not
reject the null hypothesis because -0.879 lies in the region between +2.326 and
-2.326.
Reject the
null hypothesis because 37% is less than 40%.
What are the two critical values for a two-tailed test with
a 0.01 level of significance when n is large and the population standard
deviation is known?
Above 2.58
and below -2.58
Above 0.68
and below -0.68
Above 2.26
and below -2.26
Above 1.00
and below -1.00
Two samples, one of size 15 and the second of size 13, are
selected to test the difference between two population means. How many degrees
of freedom are used to find the critical value? Assume the population standard
deviations are equal.
15
25
28
27
26
A hypothesis regarding the weight of newborn infants at a
community hospital is that the mean is 11.3 pounds. A sample of seven infants
is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0,
8.8, 6.8, 8.4, and 11.3 pounds. The null hypothesis is
H0: µ =
11.3
H0: µ >
12.3
H0: µ ≥
11.3
H0: µ ≤
12.3
21 The annual dividend rates for a random sample of 16
companies in three different industries, utilities, banking, and insurance were
recorded. The ANOVA comparing the mean annual dividend rate among three
industries rejected the null hypothesis that the dividend rates were equal. The
Mean Square Error (MSE) was 3.36. The following table summarized the results:
Picture
Based on the comparison between the mean annual dividend
rate for companies in utilities and banking, the 95% confidence interval shows
an interval of 1.28 to 6.28 for the difference. This result indicates that
_____________________.
The annual
dividend rate in the banking industry is significantly less than the annual
dividend rate in the utilities industry
The
interval contains a difference of 5.00
There is no
significant difference between the two rates
The annual
dividend rate in the utilities industry is significantly less than the annual
dividend rate in the banking industry
23 the regression equation is Ŷ = 30 + 2.56X, the sample
size is 14, and the standard error of the slope is 0.97. What is the
test-statistic to test the significance of the slope?
z = +2.639
t = +2.560
z = -2.560
t = +2.639
50 Given the following Analysis of Variance table for three
treatments each with six observations.
Source Sum of Squares df Mean Square
Treatments 1,182
Error 1,042
Total 2,224
What is the computed
value of F?
8.51
9.70
9.49
7.94
49 A grouped frequency distribution has a mean of 100 and a
standard deviation of 20. The class limits for one class are 50 and 60. Based
on the normal distribution, what is the probability that an observation would
be in this class?
0.2272
0.0165
-0.0165
0.4938
47 A sample of 250 adults tried the new multigrain cereal
"Wow!" A total of 187 rated it as excellent. In a sample of 100
children, 66 rated it as excellent. Using the 0.1 significance level, the
researcher wishes to show that adults like the cereal better than children.
What is the pooled proportion?
0.494
1.408
0.807
0.723
46 The average cost of tuition, room and board at small
private liberal arts colleges is reported to be $8,500 per term, but a
financial administrator believes that the average cost is higher. A study
conducted using 350 small liberal arts colleges showed that the average cost
per term is $8,745 with a standard deviation of $1,200. Let formula4.mml =
0.13. What is the critical z-value for this test?
-1.44
+1.44
+1.13
-1.13
45 For a hypothesis comparing two population means, what is
the critical value for a one-tailed hypothesis test, using a 5% level of
significance level, with both sample sizes equal to 18? The standard deviations
for the samples are 16 and 18. Assume the population standard deviations are
unequal.
2.192
1.742
1.692
1.269
To test the hypothesis that 55% of those families who plan
to purchase a vacation residence in Florida want a condominium, the null
hypothesis is π = 0.55 and the alternate is π ≠ .55. A random sample of 400
families who planned to buy a vacation residence revealed that 228 families
want a condominium. What decision should be made regarding the null hypothesis
using the 0.01 level of significance?
Reject it.
Do not
reject it.
Purchase a
condominium.
To test the hypothesis that 55% of those families who plan
to purchase a vacation residence in Florida want a condominium, the null
hypothesis is π = 0.55 and the alternate is π ≠ .55. A random sample of 400
families who planned to buy a vacation residence revealed that 228 families
want a condominium. What decision should be made regarding the null hypothesis
using the 0.01 level of significance?
Reject it.
Do not
reject it.
Purchase a
condominium.
Cannot
accept it or reject it based on the information given. Cannot accept it or reject it based on the information given.
42 A recent study of the relationship between social
activity and education showed the following results.
Social Activity
Education Above Average Average Below
Average
College 28 20 8
High School 18
40 106
Grade School 8 50 126
What is the value of the test statistic?
92.58
20.20
5.45
67.33
41 A regression analysis yields the following information:
Picture ; n = 10;
sy∙x = 1.66; ΣX = 32; ΣX2 = 134; Picture
Compute the 95% confidence interval when X = 4.
6.842,
9.497
4.15, 12.25
0.0, 4.05
2.67, 5.33
40.value:
2.00 points
Two accounting professors decided to compare the variance of
their grading procedures. To accomplish this, they each graded the same 17
exams with the following results:
Mean Grade Standard Deviation
Professor 1 81.5
26.8
Professor 2 88.4
13.9
The calculated F ratio is
5.863
3.717
2.146
1.492
39.value:
2.00 points
A personnel manager is concerned about absenteeism. She
decides to sample the records to determine if absenteeism is distributed evenly
throughout the six-day workweek. The null hypothesis to be tested is:
Absenteeism is distributed evenly throughout the week. The 0.4 level is to be
used. The sample results are:
Day of Week Number Absent
Monday 52
Tuesday 69
Wednesday 51
Thursday 30
Friday 69
Saturday 29
How many degrees of freedom are there?
5
4
3
6
37.value:
2.00 points
A regression analysis yields the following information:
formula47.mml
formula48.mml
Compute the 90% prediction interval when X = 6.
10.44,
12.76
10.82,
13.38
8.02, 15.18
5.38, 6.30
36 Several employees have submitted different methods of
assembling a subassembly. Sample data for each method are:
Picture
How many treatments are there?
0
12
4
3
35 A hypothesis regarding the weight of newborn infants at a
community hospital is that the mean is 6.6 pounds. A sample of seven infants is
randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0,
8.8, 6.8, 8.4, and 6.6 pounds. The null hypothesis is ______.
H0: µ ≥ 6.6
H0: µ = 6.6
H0: µ >
7.6
H0: µ ≤ 7.6
33 A sales manager for an advertising agency believes that
there is a relationship between the number of contacts that a sales person
makes and the amount of the sales dollars earned.
A regression analysis shows the following results:
Coefficients Standard Error t
Stat P-value
Intercept 4.799
6.530 0.735 0.500
Number of Contacts 2.280 0.155 14.710 0.000
ANOVA
df SS MS F Significance F
Regression 1.00
13,650.94 13,650.94 485.97 0.00
Residual 25.00
702.32 28.09
Total 26.00
14,353.26
formula32.mml
The 90% confidence interval for 13 calls is
42.57,
32.57
31.08,
37.80
16.30,
47.30
33.57,
43.57