What is the comparison distribution in a t test for independent means? Explain the logic of going from scores in two samples to an estimate of the variance of this comparison distribution. Why is the mean of this distribution 0?
Twenty students randomly assigned to an experimental group receive an instructional program; 30 in a control group do not. After 6 months, both groups are tested on their knowledge. The experimental group has a mean of 38 on the test (with an estimated population standard deviation of 3); the control group has a mean of 35 (with
Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24-hour cycle of sleeping and waking-even if they are not exposed to the usual pattern of sunlight. To test this notion, eight paid volunteers were placed (individua
52. The president of the American Insurance Institute wants to compare the yearly costs of auto insurance offered by two leading companies. He selects a sample of 15 families, some with only a single insured driver, others with several teenage drivers, and pays each family a stipend to contact the two companies and ask for a pri
2. Suppose you want to test the claim that population mean miu=3.5. Given a sample size of n=34 and a level of significance of alpha=0.01, when should you reject Ho? 3. Find the standardized test statistic t for a sample with n=15, sample mean=8.7, s=0.8, and alpha =0.05 if Ho is less than or equal to 8.4. 4. Find the sta
EXERCISE #1: DATA LOADING & DESCRIPTIVE STATISTICS. Imagine that stimulus students are asked to indicate how likely they are to use a new breakfast-food/ toothpaste combination. The rating scale ranges from 0 (no chance of using the product) to 100 (certain to use the product). Your trustworthy but confused lab assistant han
Grand Strand Family Medical Center is specifically set up to treat minor medical emergencies for visitors to the Myrtle Beach area. There are two facilities, one in the Little River Area and the other in Murrells Inlet. The Quality Assurance Department wishes to compare the mean waiting time for patients at the two locations. Sa
The engineer in a widget factory wants to test out a new form of raw materials. So a batch of widgets are made in the old manner as a control group and then a batch are made with the new materials as a comparison. If the average widget weight is statistically the same on both sets, the new materials will be used. The weights
Please see attachment. I need help with the highlighted parts. Hypothesis test for the difference of population means: t test Medical researchers interested in determining the relative effectiveness of two different drug treatments on people with a chronic mental illness established two independent test groups. The first gr
Implement raw data tables and computations, using both graphical and tabular methods of displaying data and results The US economy is in crisis brought on by the financial markets, the deep slump of the housing, high unemployment, and the slowdown of consumer spending. This has caused problems for buyers and sellers in the
Members of the general adult population volunteer an average of 4.2 hours per week. A random sample of 20 female college students and 18 male college students produced the results given in the table below. Assuming that the variances of the time volunteered by females and males are equal, at the .01 level of significance, is t
A pharmaceutical company is testing the effectiveness of a new drug for lowering cholesterol. As part of this trial, they wish to determine whether there is a difference between the effectiveness for women and for men. At = .05, what is the value the test statistic? Women Men Sample size 50 80 Mean
Part 1 Biting an unpopped kernel of popcorn hurts! As an experiment, a self-confessed connoisseur of cheap popcorn carefully counted 773 kernels and put them in a popper. After popping, 66 unpopped kernels were counted. A. Construct a 90% confidence interval for the proportion of all kernels that would not pop. 1. What
Let's say I have 2 hypothesis. Alternate hypothesis: I will save more than 100,000 by utilizing other cost cutting measures other than layoffs. Null Hypothesis: The company will save 100,00 by the layoff of employess across the company and it's a far less risking process. Question: Can I denote my hypothesis numeric
Please see the attached formulas. DQ 3.3 From Lind Chapter 10: One-sample Test of Hypothesis. Two formulas are shown below, explain the differences in then, and describe when you would use each of the formula.
An experimental surgical procedure is being studied as an alternative to the old method. Both methods are considered safe. Five surgeons perform the operation on two patients matched by age, sex, and other relevant factors, with the results shown. The time to complete the surgery (in minutes) is recorded. At the 5% significa
Z test At a retail store, customer survey is South Dallas the average household income of 75 household showed $90K with standard deviation of $25K. At another store in North Dallas, the household income of 60 households surveyed showed $120K with standard deviation of $30K. At significance level of 0.07, can a research anal
The management of White Industries is considering a new method of assembling its golf cart. The present method requires 42.3 minutes, on the average, to assemble a cart. The mean assembly time for a random sample of 24 carts, using the new method, was 40.6 minutes, and the standard deviation of the sample was 2.7 minutes. Using
1) Survey showed 75 new employees hired at one employment place had an average salary of $60K with standard deviation of $20K. At another employment place, the average income of 60 households surveyed showed $85K with standard deviation of $25K. At significance level of 0.05, can a surveyor conclude that population means are dif
In a test of a new surgical procedure, five respected surgeons in FlatBroke Township were invited to Carver Hospital. Each surgeon was assigned two patients of the same age, gender, and overall health. One patient was operated upon in the old way, and the other in the new way. Both procedures are considered equally safe. The tim
Clark Heter is an industrial engineer at Lyons Products. He would like to determine whether there are more units produced on the afternoon shift than on the day shift. A sample of 54 day-shift workers showed that the mean number of units produced was 345, with a standard deviation of 21. A sample of 60 afternoon-shift workers
(a) At alpha (a) =.05, does the following sample show that daughters are taller than their mothers? (b) Is the decision close? (c) Why might daughters tend to be taller than their mothers? Why might they not? Family Daughters Height(CM) Mothers Height (CM) 1 167 172 2 166
If 15 subjects take a pre-test and a post-test with a mean change score of 1.5, and if the standard deviation of the comparison distribution is calculated to be .5, what is the t score? A. 1.5/(15-1)=0.11 B. 1.5/15=0.10 C. 1.5/.5=3.00 D. 1.5/(.5(15-1)=0.21 A school counselor claims that he has developed a technique
One group of accounting students took a distance learning class, while another group took the same course in a traditional classroom. At £ = .10, is there a significant difference in the mean scores listed below? (a) State the hypotheses. (b) State the decision rule and sketch it. (c) Find the test statistic. (d) Make a deci
In two independent samples, from populations that are normally distributed , x1 = 35.0, s1 = 5.8, n1 = 12 and x2 = 42.5, s2 = 9.3, n2 = 14. Using the 0.05 level of significance, test Ho:u1 versus H1:u1 = u2. 2. The product development team for a notebook computer company has shown picture A to a large sample of potential bu
In a study it took an average of 2.1 minutes to locate information and buy products on the Delta Airlines website, compared to an average of 2.7 minutes on the British Airways site. Assume that the data file contains the times (in minutes) required during visits to the two websites. In a suitable one-tail test at the 0.01 leve
Want you to explain step by step i want to understand more than the answer I got... 9.57 A manufacturer of chocolate candies uses machines to package candies as they move along a filling line. Although the packages are labeled as 8 ounces, the company wants the packages to contain 8.17 ounces so that virtually none of the packa
10. a restaurant manager wants to compare mean daily sales between two of his restaurants located several miles apart in the same city. For a one-week period the following sales data are recorded. Sunday: restaurant 1 (1916) restaurant 2 (1771) Monday: restaurant 1(991) restaurant 2 (904) Tuesday: restaurant 1 (1112) restaura
2.The A.C. Nelson Company Collects Data on the TV viewing habits of Americans and publishes the information in the Nielson report on television. 20 married couples are randomly selected. Their weekly viewing times, in hours are as follows Husband: 21,56,34,30,41,35,26,38,27,30,31,30,32,15,36,20,43,4,16,21 Wife: 24,55,55,34
1. Find the Z -score and percentiles for the following calculations. Interpret your findings: a) Distribution of scores: Mean= 80 Standard Deviation=5 Scores are: X= 68, 75, 64 and 54 b) A researcher is testing a null hypothesis at the 0.05 level, would you accept or reject the null hypothesis? Z= -2.30 Z= 0.