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# Hypothesis Testing

### Baby Birth Weights and Mother Cocaine Use Study

A random sample of the birth weights of 186 babies has a mean of 3103g and a standard deviation of 696g (based on data from "Cognitive Outcomes of Preschool Children with Prenatal Cocaine Exposure," by Singer et al., Journal of the American Medical Association, Vol. 291, No. 20). These babies were born to mothers who did not us

### Non-Parametric Test on Software Adoption

Company W is testing a sales software. Their sales force of 500 people is divided into four regions: Northeast, Southeast, Central and West. Each sales person is expected to sell the same amount of products. During the last 3 months, only half of the sales representatives in each region were given the software program to help th

### Statistical Testing - T Tests and Proportions

1. Do men and women have different beliefs on the ideal number of children in a family? Based on the following GSS2008 Data and the obtained t statistics, what would you conclude? (0.05) Men Women Mean ideal number of children 3.06

### The Importance of Statistical Significance

What is more important statistical or practical significance? Why?

### Relative Risk Example Problem

A multicenter clinical trial involving 17,000 patients suspected of having acute myocardial infarction was conducted. The vascular death rate after 5 weeks was compared in patients receiving aspirin versus those not receiving aspirin, regardless of any other concomitant treatment. The relative risk (RR) for the effect of aspirin

### Distribution Analysis: Statistics for Business Textbook Problems

6.8 For each of the following rejection regions, sketch the sampling distribution for z and indicate the location of the rejection region. a. z>1.96 b. z>1.645 c. z>2.575 d. z<-1.28 e. z<-1.645 or z>1.645 f. z<-2575 or z>2.575 g. For each of the rejection regions specified in parts a-f, what is the probability that a Typ

### Statistics Variance Problem

We are interested in determining whether or not the variances of the sales at two music stores (A & B) are equal. A sample of 10 days of sales at store A has a standard deviation of 30, while a sample of 16 days of sales from store B has a standard deviation of 20. 1) What is the value of the Observed test statistic? 2) What

### "T" Value & Developing a Research Question

Calculate the "t" value for independent groups for the following data using the formula presented in the module. Check the accuracy of your calculations. Using the raw measurement data presented above, determine whether or not there exists a statistically significant difference between the salaries of female and male human resou

A researcher interviewed 2067 people and asked whether they were the primary decision makers in the household when buying a new car last year. Two hundred seven were men and had bought a new car last year. Sixty-five were women and had bought a new car last year. Eight hundered eleven of the responses were men who deid not buy a

### Statistics and Estimating

1. Suppose a wildlife service wishes to estimate, with 99% confidence, the mean number of days of hunting per hunter for all licensed hunters in the state during a given season, with a bound on the error of estimation equal to 2 hunting days. How many hunters must be included in the survey? Assume that the data collected in earl

### Statistical T-Tests for Means

The publisher of Celebrity Living claims that the mean sales for personality magazines that feature people such as Angelina Jolie or Paris Hilton are 1.5 million copies per week. A sample of 10 comparable titles shows a mean weekly sales last week of 1.3 million copies with a standard deviation of 0.9 million million copies. Doe

### Critical Value and Z Statistic

Use the critical values for z of 1.65 and a p level of approximately 0.10, or 10%. For each of the following values, determine if you would reject or fail to reject the null hypothesis: a. z  0.95 b. z  1.77 c. A z statistic that 2% of the scores fall above

### Mean and Spread of the Comparison Distribution

If you are performing a hypothesis test using a z statistic in which you sampled 50 people and found an average SAT verbal score of 542 (assume we know the population mean to be 500 and the standard deviation to be 100), calculate the mean and spread of the comparison distribution.

### Independent Measures and Difference between Treatments

The following data were obtained from an independent measures study. Determine if there is a significant difference between the treatments. Use alpha = .01. Treatment 1 Treatment 2 5 6 1 10 2 14 3 12 4

### Testing the Different Performance of Students with and without Sleep

a. Research has shown that losing a few hours of sleep can have a significant effect on performance of some simple tasks. To demonstrate this phenomenon, a sample of n = 25 college students was given a simple problem solving task at noon one day and again at noon on the following day. The students were not permitted any sleep a

### Sensitivity and Specificity

Hypertension As part of a study performed in Norway, 70,000 people in the general population had their blood pressure measured; two readings were obtained and the second reading was used in the analysis. The people were followed for mortality outcome over a 10-year period after the blood-pressure measurement using death files

### How large would your population have to be for a sample to be appropriate?

How large would your population have to be for a sample to be appropriate (i.e., rather than measuring the whole population)?

### Goodness of Fit Test: Telephone Calls Received

8. During 200 randomly selected minutes, the number of telephone calls received each minute were recorded. At the .05 level of significance, is there any evidence that these data are not Poisson with a mean of 2.8? Number of Calls Per Observed Minute

### Statistics: College Writing Scores

State college is evaluating a new english composition course for freshmen. A random sample of N=25 freshmen is obtained and the students are placed in the course during their first semester. One year later, a writing sample is obtained for each student and the writing samples are graded using a standard evaluation technique. The

### Research Paper: Major, Age and Gender

Examine the variables in the data file 2004GSS.sav in terms of their labels and values. Develop a research paper with the five sections described below. You should submit your report as one MSWord document with all data and tables copied into that document. Introduction: The purpose of the paper. Rewrite this section after co

### Statistics Test Mutual Funds Question

Please help with the following statistics test and mutual funds problems. Step by step calculations are given. Fidelity Magellan is a large cap growth mutual fund and Fidelity Small Cap Stock is a small cap growth mutual fund (Morningstar Funds 500, 2006). The standard deviation for both funds was computed based on a sample

### Determining Statistical Differences

The general manager of an airline recently noticed an increase in the number of no shows for flights from Calgary. He wants to know if there are a different number of no shows for flights from Calgary compared with flights from Toronto. Below are the numbers of no shows for the flights: Calgary 11,15,10,18,11,20,24,22,25 To

### Random Selection of Nonfatal Occupations

Randomly selected nonfatal occupational injuries and illnesses are categorized, according to the day of the week that they first occured, and the results are listed below. Use a 0.05 significance level to test the claim that such injuries and illnesses occur with equal frequency on the different days of the week. Please show y

### Analyzing proportion claims

A certain researcher thinks that the proportion of women who say that female bosses are harshly critical is greater than the proportion of men. In a random sample of 200 women, 27% said that female bosses are harshly critical. In a random sample of 220 men, 25% said that female bosses are harshly critical. At the 0.05 sig

### Hypothesis Testing Rejection and P-Values

Consider the hypothesis test given by H0: u =530 H1: u does not = 530 In a random sample of 85 subjects, the sample mean is found to be 522.3. Also, the population standard deviation is 29. Determine the p-value for this test. Is there sufficient evidence to justify the rejection of H0 at the "alpha" level of 0.01? Please

### Sample Mean, Sample Standard Deviation, Conclusion of Test

Given a sample size of 65, with sample mean 726.2 and sample standard deviation 85.3, we perform the following hypothesis test. H0: u = 750 H1: u < 750 1. What is the conclusion of the test at the "alpha" = 0.10 level? Please explain your answer.

### Injuries and Motorcycle Helmet Color

A case-control study was conducted to investigate a relationship between the colors of helmets worn by motorcycle drivers and whether they are injured or killed in a crash. Results are given in the table below. Test the claim that injuries are independent of helmet color. Should motorcycle drivers choose helmets with a particula

### Testing a Claim using Significance Testing

Test the given claim - Global warming survey: A Pew research poll was conducted to investigate opinions about global warming. The respondents who answered yes when asked if there is solid evidence that the earth is getting warmer were then asked to select a cause of global warming. The results for two age brackets are give

### Statistics Hypothesis Test: Flat Tire

A classic tale involves for carpooling students who missed a test and gave as an excuse a flat tire. On the makeup test, the instructor asked the students to identify the particular tire that went flat. If they really didn't have a flat tire, would they be able to identify the same tire? The author asked 41 other students to ide

### Statistics: Testing a Null Hypothesis

A researcher is testing a null hypothesis that states: Ho: = 50. A sample of 25 scores is selected and the mean is M = 55. Assuming that the sample variance is 100, compute the estimated standard error and the t statistic. Is this sample sufficient to reject the null hypothesis using a two-tailed test with alpha = .05? Ass