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Hypothesis Testing

Hypothesis Testing: Independent Sample t Test..

See the attached file for the data. Insurance adjusters are concerned about the high estimates they are receiving from Jocko's Garage. To see if the estimates are unreasonably high, each of 10 damaged cars was taken to Jocko's and to another garage and the estimates recorded. Here are the results: Test the null hypothesi

Conducting a hypothesis test for a population mean

Please help with the following problem. You have a sample size of 120 and the population standard deviation of 20. You are testing the null hypothesis of whether the population mean is 120 or not. A. What are the critical values for rejection when Type I error is 5%? B. If actual mean is 121, find the Type II error C.

Pew Research Automobiles Driving

8.14 Do you enjoy driving your car? The Pew Research Center recently polled n = 1048 U. S. drivers and found that 69% enjoyed driving their automobiles. (a) Construct a 95% confidence interval for the proportion of U. S. drivers who enjoy driving their automobiles. (b) In 1991, a Gallup Poll reported this percent to be 79%


1. Different neighbourhoods may have different crime statistics. A sample of 10 days in Neighbourhood A revealed the following number of crimes per day: 15 12 16 17 15 14 16 10 12 14 A sample of 12 days in Neighbourhood B revealed the following number of crimes per day: 17 13 15 18 16 19 11 21 22 13 16 18 At a 5% l

Testing blood lipid levels

More on blood lipid levels. LDL is also known as ' bad' cholesterol. Suppose the researchers wanted to test the hypothesis that LDL levels are higher in sedentary males than in sedentary females. Describe appropriate null and alternative hypotheses and carry out the significance test using a = 0.05. Report the test statistic wit

Sample of NHTSA Conducted Crash Tests of Child Booster Seats

The NHTSA conducted crash tests of child booster seats for cars. Listed below are results from those tests, with the measurements given in hic (standard head injury condition units). The safety requirement is that the hic measurement should be less than 1000 hic. Use a 0.01 significance level to test the claim that the sample is

Statistics: Does ad placement matter?

Does ad placement matter? Corporate advertising tries to enhance the image of the corporation. A study compared two ads from two sources, the Wall Street Journal and the National Enquirer. Subjects were asked to pretend that their company was considering a major investment in Performax, the fictitious sportswear firm in the ads.

Statistics: Analysis of food intake and weight gain

Food intake and weight gain. If we increase our food intake, we generally gain weight. Nutrition scientists can calculate the amount of weight gain that would be associated with a given increase in calories. In one study, 16 nonobese adults, aged 25 to 36 years, were fed 1000 calories per day in excess of the calories needed to

Average annual income of dentists in 2005 was $110,000.

The Bureau of Labor Statistics reported that the average annual income of dentists in the year 2005 was $110,000. A sample of 81 dentists, which was taken in 2006, showed an average annual income of $115,000. Assume the standard deviation of the population of dentists in 2006 is $36,000. a). Suppose you want to test whether t

Calculating Mean and Standard Deviation: New Jobs Example

The Department of Economic and Community Development (DECD) reported that in 2008 that average number of new jobs created per county was 450. The department also provided that following information regarding a sample of five counties in 2009. Bradley 410 Rhea 450 Marion 407 Grundy 428 Sequatchie

Statistics: Tessler Electric utility, sample of telephone response time

Tessler Electric utility requires service operators to answer the telephone calls from customers in an average time of 0.1 minute or less. A sample of 30 actual operator times are drawn, and the results are given in the following table. In addition, operators are expected to determine customer needs and either respond to them

7-11 Find the critical values

See attached file for full problem. 7-11. Do one of the following, as appropriate. (a) find the critical value (b) find the critical value (c) State that neither the normal nor the t distribution applies. Confidence level 90%; n = 16; o is known; population appears to be very skewed. Find the critical values: a.

Minimum sample size given margin of error

7-8. Use the given margin of error, confidence level, and population standard deviation (o) to find the minimum sample size required to estimate an unknown population means (u) Margin of error: 0.5 inches, confidence level: 90%, o=2.7 inches A confidence level of 90% requires a minimum sample size of ______

Professor Pink Panther's test; Dr. Sehr Kurz's summary data

Quiz #4 Professor Pink Panther is a referee (reviewer) for a prestigious international journal, Manuscripta Absurda. Recently, he is giving two articles to review. The following information is for Questions 1 through 5. There are two personality types, Type-A and Type-B. Married couples are made up of three

Estimate weight of M&Ms

A data set of red and orange M&M's yield the following sample weight data. Use the 0.05 significance level to test for equality of the two population means using the traditional approach to hypothesis testing. Red M&M's n1 = 21 x1 = 0.9097 grams s1 = 0.0275 grams Orange M&M's n2 = 8 x2 = 0.9251 grams s1 = 0.0472 g

Test driving habits of women age 16-24

The insurance company is reviewing the driving habits of women aged 16-24 to determine if they should continue to pay higher premiums than women in a higher age bracket. In a study of 750 rendomly selected women drivers aged 16-24, the mean driving distance for one year is 6900 miles. The population standard deviation is 2944

Statistics: Clinical Trial for New Compound

A clinical trial was conducted comparing a new compound designed to improve wound healing in trauma patients to a placebo. After treatment for 5 days, 58% of the patients taking the new compound had a substantial reduction in the size of their wound as compared to 44% in the placebo group. The trial failed to show significance.

Statistical Problems for Standard Deviation Distribution

Problem 2b: For a population that has a standard deviation of 10, figure the standard deviation of the distribution of means for samples of size- (b) 3. Problem 6: For each of the following samples that were given an experimental treatment, test whether these samples represent populations that are different from the general

Computing the Mean, Standard Deviation, and Testing Hypothesis

Show all work. A group of young businesswomen wish to open a high fashion boutique in a vacant store, but only if the average income of households in the area is at least $25,000. A random sample of 9 households showed the following results: $28,000 $23,000 $24,000 $24,000 $27,000 $26,000 $26,000 $25,000 $22

Critical value approach, p- value approach for sample

Show all work. A sample of 30 cookies is taken to test the claim that each cookie contains at least 9 chocolate chips. The average number of chocolate chips per cookie in the sample was 7.8 with a standard deviation of 3. -State the null and alternative hypotheses -Using the critical value approach, test the hypotheses at

Null and Alternative Hypothesis for Filling Soft Drink Bottles

A soft drink filling machine, when in perfect adjustment, fills the bottles with 12 oz. of soft drink. Any over filling or under filling results in the shutdown and readjustment of the machine. -To determine whether or not the machine is properly adjusted, the correct hypothesis is: a) Ho: μ < 12 H1: Μ ≤

Statistics: Hypothesis testing, p-value, confidence level

Please show all work: A random sample of 16 students selected from the student body of a large university had an average age of 25 years and a standard deviation of 2 years. We want to determine if the average age of all the students at the university is significantly more than 24. Assume the distribution of the population of

P-Value, Confidence Level for Hypothesis Testing

All work must be shown. Question 1 n=36 xbar =24.6 s= 12 Ho: Mâ?¤20 Ha: M > 20 -The statistc test is: a) 2.3 b) 0.38 c) .2.3 d-0.38 -The p-value is between: a) 0.005 to 0.001 b) 0.01 to 0.025 c) 0.025 to 0.05 d) 0.05 to 0.10 -If the test is done at 95% confidence, the null hypothesis should: a) Not be

Testing null and alternative hypothesis

Establish a null and alternative hypothesis about the mean of the original popoulation of data, test the sample results against the population, esplain the relationship between your sample data and the population based on the results of the hypothesis test. # of items sold 63 88 102 34 57 70 125 12 15 44

Example-Single population proportion tested using two-tail

Cite an example of how you could/would apply a test of a hypothesis for a single population proportion, two tail test described in the lecture to real world situations? Make sure you state your hypothesis in both the null and alternate form as well as shoing the hypotheses in symbol form.

Forecast: Thiel's U Statistic, ME, MSE, RMSE, MAPE and Forecast Error

See attached Excel data file. For each forecast, set up columns and calculate: Error Squared error Absolute error Absolute % error The numerator of Thiel"s U statistic The denominator of Thiel"s U statistic Calculate ME, MSE, RMSE, MAPE, and U. Questions. 1/ The absolute percentage error for the data point 9/24/

Hypothesis Testing of Mean: Actual & Ideal Weights

13.28) In a study, results were presented for a sample of 63 men who were asked to report their actual weight and their ideal weight. The mean difference between actual and ideal weight was 2.48 pounds, and the standard deviation of the differences was 13.77 pounds. Is there sufficient evidence to conclude that for the popul

Hypothesis Testing of Mean: Tire Pressure

13.17) An exercise posed the following research question: Many cars have a recommended tire pressure of 32 psi (pounds per square inch). At a roadside vehicle safety checkpoint, officials plan to randomly check select 50 cars for which this is the recommended tire pressure and measure the actual tire pressure in the front left