Web Calculator Exercise 2
Daniel Alvarado
Liberty University

Z test & One sample t-test

1. A researcher is interested in whether students who attend private high schools have higher average SAT Scores than students in the general population. A random sample of 90 students at a private high school is tested and and a mean SAT score of 1030 is obtained. The average score for public high school student is 1000 (σ= 200).

a. Is this a one- or two tailed test?
This test is a one – tailed test, because the researcher wants to know that students who attend private high school will have a higher Sat score, which makes the alternative hypothesis a prediction in favor of the private school over the public high school.

b. What are H0 and Ha for this study?
The Hₒ foe the study is that the mean of the private school will be less than the mean from the public school. The Hₐ for this study is that the mean of the public school is higher than the mean for the public school.

c. Compute Z obt
To compute the Z obt we take the 200 which is the standard diviation and the 90 which is the sample size and plug in to the formula for standard error: 200divided by the square root of 90 = 21.082

d. What is the Z critical value (Z cv ) using a 0.05 alpha level?

Z cv for 005 alpha level is -1.6449

e. Should H0 be rejected? What should the researcher conclude?

H0 should not be rejected because there is not a large difference between both means.

f. Determine the 95 % confidence interval for the population mean, based on the sample mean.

Confidence level for population mean is less than 988.680 and higher than 1071.320 http://easycalculation.com/statistics/confidence-limits-mean.php

2. A researcher hypothesized that the pulse rates of long-distance athletes differ from those of other athletes. He...

... Standard Deviation = 10.74832
Web address: http://easycalculation.com/statistics/standard-deviation.php
Frequency distribution table for denomination.
Score f(frequency)
1 1
22
4 2
5 1
6 3
7 3
8 1
9 3
10 3
12 1
N=30
c. What is the percentage of people who identify themselves as Baptist?
3/20 = .15 x 100 = 15%
What is the mode of church...

...M02_MARI6128_10_SE_CH02.QXD
1/17/11
8:15 PM
Page 25
NAME_________________________________ LAB TIME/DATE ________________________
R E V I E W
S H E E T
EXERCISE
9/1/2012
2
Organ Systems Overview
1. Use the key below to indicate the body systems that perform the following functions for the body. Then, circle the organ systems (in the key) that are present in all subdivisions of the ventral body cavity. Key: a. b. c. cardiovascular...

...In dealing with non-pooled statistics in two different scenarios, or samples in this case. One is Standard Deviations and Assumed Equal. You can be somewhat certain that the populations have nearly equal standard deviations, and then you should use a pooled-t method. If you were really uncertain then you would use a non-pooled t-method. And with the SRS’s separate samples or normal populations, large samples are not satisfied; then the non-pooled-t methods should not be used.
As for two...

...Statistics
b. Identify the outlier. If it is removed, does your conclusion change for the 5% significant level test in a. (carry out the final test again assuming no change in your conclusion about your test on variances in part a.) (5 marks)
2. Exercises 8-3; Question number 14 of the text (Triola). The Alberta government records freezing dates for over a hundred locations around the province. Based on average last frost dates for spring, a researcher has...

...Web Calculator Exercise 5
ANOVAs
1. A researcher is interested in comparing the effectiveness of three different kinds of therapy for anger problems. Eight participants are randomly assigned to three treatment conditions: Cognitive Therapy (CT), Cognitive-Behavioral Therapy (CBT), and Interpersonal Therapy (IT). All participants complete the weekly treatment for 8 weeks. Participants take an anger test before and after the 8-week treatments. Each...

...Web Calculator Exercise 1
Descriptive Statistics
1. The table below presents data for a sample of people who completed a religious survey.
|Age |Gender |Denomination |Church Attendance |
|56 |1 |7 |4 |
|46 |2 |6 |5 |
|49 |2 |6 |5...

...Chapter 2 Assignment
Ryan M. Kethcart
INFOST-491 SEC-OL
Exercises
1. Consider the statement: an individual threat agent, like a hacker, can be a factor in more than one threat category. If a hacker hacks into a network, copies a few files, defaces the Web page, and steals credit card numbers, how many different threat categories does this attack fall into?
a. Overall, I believe this attack falls into four major threat categories:...

...WEB SEARCH 2
1. What is the purpose of financial statement analysis? The purpose of financial statement analysis is to provide information used by the business, potential creditors and investors.
2. If a company had sales of $2,587,643 in 1998 and sales of $3,213,456 in 2003, by what percentage did sales change during this time period? 24.18%
a. If the company had a goal of increasing sales by 25% over a five-year...