Essentials of Statistics for the Behavioral Sciences
8th Edition
ISBN: 9781133956570
Author: Frederick J Gravetter, Larry B. Wallnau
Publisher: Cengage Learning
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Chapter 8.1, Problem 1LC
The city school district is considering increasing class size in the elementary schools. However, some members of the school board are concerned that larger classes may have a negative effect on student learning. In words, what would the null hypothesis say about the effect of class size on student learning?
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Calculate the 90% confidence interval for the population mean difference using the data in the attached image. I need to see where I went wrong.
Microsoft Excel snapshot for random sampling: Also note the formula used for the last
column
02
x✓ fx =INDEX(5852:58551, RANK(C2, $C$2:$C$51))
A
B
1
No.
States
2
1
ALABAMA
Rand No.
0.925957526
3
2
ALASKA
0.372999976
4
3
ARIZONA
0.941323044
5
4 ARKANSAS
0.071266381
Random Sample
CALIFORNIA
NORTH CAROLINA
ARKANSAS
WASHINGTON
G7
Microsoft Excel snapshot for systematic sampling:
xfx INDEX(SD52:50551, F7)
A
B
E
F
G
1
No.
States
Rand No. Random Sample
population
50
2
1 ALABAMA
0.5296685 NEW HAMPSHIRE
sample
10
3
2 ALASKA
0.4493186 OKLAHOMA
k
5
4
3 ARIZONA
0.707914 KANSAS
5
4 ARKANSAS 0.4831379 NORTH DAKOTA
6
5 CALIFORNIA 0.7277162 INDIANA
Random Sample
Sample Name
7
6 COLORADO 0.5865002 MISSISSIPPI
8
7:ONNECTICU 0.7640596 ILLINOIS
9
8 DELAWARE 0.5783029 MISSOURI
525
10
15
INDIANA
MARYLAND
COLORADO
Suppose the Internal Revenue Service reported that the mean tax refund for the year 2022 was $3401. Assume the standard deviation is $82.5 and that the amounts refunded follow a normal probability distribution. Solve the following three parts? (For the answer to question 14, 15, and 16, start with making a bell curve. Identify on the bell curve where is mean, X, and area(s) to be determined.
1.What percent of the refunds are more than $3,500?
2. What percent of the refunds are more than $3500 but less than $3579?
3. What percent of the refunds are more than $3325 but less than $3579?
Chapter 8 Solutions
Essentials of Statistics for the Behavioral Sciences
Ch. 8.1 - The city school district is considering increasing...Ch. 8.1 - Prob. 2LCCh. 8.1 - Prob. 3LCCh. 8.1 - A researcher selects a sample of n = 16...Ch. 8.1 - A small value (near zero) for the z-score...Ch. 8.1 - Prob. 3LCACh. 8.2 - Prob. 1LCCh. 8.2 - Prob. 2LCCh. 8.2 - Prob. 3LCCh. 8.2 - Prob. 4LC
Ch. 8.2 - If a sample mean is in the critical region with =...Ch. 8.3 - Prob. 1LCCh. 8.3 - In a research report, the term significant is used...Ch. 8.3 - Prob. 3LCCh. 8.3 - Prob. 4LCCh. 8.3 - Prob. 5LCCh. 8.4 - A researcher selects a sample from a population...Ch. 8.4 - Prob. 2LCCh. 8.4 - A researcher obtains z = 2.43 for a hypothesis...Ch. 8.5 - Prob. 1LCCh. 8.5 - A researcher selects a sample from a population...Ch. 8.5 - Prob. 3LCCh. 8.6 - Prob. 1LCCh. 8.6 - For a 5-point treatment effect, a researcher...Ch. 8.6 - Prob. 3LCCh. 8.6 - Prob. 4LCCh. 8 - The value of the z-score in a hypothesis test is...Ch. 8 - Define the alpha level and the critical region,...Ch. 8 - Although there is a popular belief that herbal...Ch. 8 - Childhood participation in sports, cultural...Ch. 8 - A local college requires an English composition...Ch. 8 - A random simple is selected from a normal...Ch. 8 - A random sample of n = 25 scores is selected from...Ch. 8 - Brunt, Rhee, and Zhong (2008) surveyed 557...Ch. 8 - A random simple is selected from a normal...Ch. 8 - In a study examining the effect of alcohol on...Ch. 8 - The researchers cited in the previous problem...Ch. 8 - There is some evidence indicating that people with...Ch. 8 - Researchers at a National Weather Center in the...Ch. 8 - Montarello and Martens (2005) found that...Ch. 8 - Researchers hate noted a decline in cognitive...Ch. 8 - A researcher plans to conduct an experiment...Ch. 8 - A sample of n = 40 is selected from a normal...Ch. 8 - Briefly explain how increasing sample size...Ch. 8 - Explain how the power of a hypothesis test is...Ch. 8 - A researcher is investigating the effectiveness of...Ch. 8 - A researcher is evaluating the influence of a...Ch. 8 - Find each of the requested values for a population...Ch. 8 - A survey of high school seniors shows that the...Ch. 8 - Miller (2008) examined the energy drink...
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