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Hypothesis Testing

Tests of hypothesis: difference between means,

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Explanation to "Test of hypothesis" question

10.10 In an attempt to improve quality many manufacturers are developing partnerships with their suppliers. A local fast-food burger outfit has partnered with its supplier of potatoes. The burger outfit buys potatoes in bags that weigh 20 lbs. It wishes to set up the null and alternative hypotheses to test if the bags do weigh

Z Scores and Percentiles

Z Scores and Percentiles Mary is a social worker who leads a treatment group of young adults diagnosed with chronic anxiety. Group members are selected for treatment based on their scores on a particular screening device, Anxiety Scale A. This instrument has a mean of 60 and a standard deviation of 12. Those scoring over 72

Sampling and hypothesis testing: test statistic, average length, preacher's sermons, stratified random sample, judgment sample, sample size, type of error, probability, proportion, confidence interval

1) A woman and her son are debating about the average length of a preacher's sermons on Sunday morning. Despite the mother's arguments, the son thinks that the sermons are more than twenty minutes. For one year, he has randomly selected 12 Sundays and found an average time of 26.42 minutes with a standard deviation of 6.69 min

Hypothesis

The quality-control manager at a lightbulb factory needs to determine whether the mean life of a large shipment of lightbulbs is equal to the specified value of 375 hours. The process standard deviation is known to be 100 hours. A random sample of 64 lightbulbs indicates a sample mean life of 350 hours a. State the null and alt

Hypothesis Testing Question

School A states the average number of days missed by each student is 4.0. Office personnel randomly sampled a portion of their attendance records to determine if this claim was accurate. For the previous year, the following data was obtained from the sample group, regarding absences for that year: 4, 4, 3, 2, 6, 8, 7, 1, 9, 3, 1

Hypothesis Testing - Compute the statistical test using the z test

A sample of 40 observations is selected from one somewhat normal population. The sample mean is 102 and the sample standard deviation is 5. A sample of 50 observations is selected from a second source. The sample mean was 99 and the standard deviation was 6. Conduct a test of the hypothesis using the .04 level of significance.

statistical test using the z test and the null

A sample of 40 households with school-age children in Middletown was randomly selected. The mean length of time was 7.6 years, with a standard deviation of 2.3 years. A sample of 55 households in Brockton revealed the mean length of time was 8.1 years, with a standard deviation of 2.9 years. At the .05 level of significance, can

Significance of difference in proportions

What I'm looking at immediately is "Using the .05 cutoff figure, find an appropriate critical region for testing the null hypothesis 'theta is greater than or equal to .154 against the alternate hypothesis 'theta is less than .154' and provide a Neyman-Pearson analysis.". Background facts for the problem: In the county, 1

Standard error of proportion, Error

Nationally the proportion of American households with income above $100,000 is 10%. A researcher in State of California finds that out of a sample of 300 households , 35 have income above $ 100,000. Can it be concluded from this sample that the proportion of households in california with income of $100,000 exceeds the proportion

Hypothesis Testing for a Retail Store Manager

Problem 1 A retail store manager is trying to estimate the average purchase transaction amount for a particular store. She takes a sample of 35 transactions and determines the mean purchase transaction amount from this same is $85 with a standard deviation of $35. a) What is the point estimate of the average purchase tran

Inference

Various types of retail outlets sell toys during the holiday season. Among them are specialty toy stores, the large discount toy stores, and other retailers that carry toys as only one part of their stock of goods. Is there any difference in the dollar amount of a customer purchase between a large discount toy store and a spec

Testing a hypothesis.

The normal serum hemocrit level is 0.41 milligrams to 100 milligrams of blood. The level in elderly patients is significantly low at 0.31. 25 patients out of 100 are normal levels. The standard deviation is 0.6. A medication that is designed to increase the hemocrit is taken in 100 patients for one month. A testing is foun

Random Sample - Test Hypotheses

PERSISTANT LOW HEMOCRIT IN ALL THE ELDERLY PATIENTS IN A NURSING HOME F .31, WITH A NORMAL OF .41. AN INTERVENTION PROGRAM OF AN IRON SUPPLEMENT WAS INITIATED TO SEE IF THE HEMOCRIT WOULD INCREASE. A RANDOM SAMPLE OF 100 PATIENTS SHOWED THAT 60 PATIENTS NOW HAD ELEVATED LEVELS OF HEMOCRIT OF .41. CAN WE CONCLUDE AT ALPHA= 0.0

Hypothesis Testing Techniques for Confidence Intervals

Use these data and hypothesis-testing techniques along with a 5% level of significance to determine whether the mean hourly wage of a manufacturing worker has changed. PROBLEM: According to the U.S. Bureau of Labor Statistics (http://www.bls.gov), the average hourly wage in the manufacturing sector in 2000 was $19.86 in th

Hypotheses Testing

A MANUFACTURER OF COMPUTER CHIPS CLAIMS THAT MORE THAN 90% OF HIS PRODUCTS CONFORM TO SPECIFICATIONS. IN A RANDOM SAMPLE OF 1000 CHIPS DRAWN FROM A LARGE PRODUCTION RUN, 875 WERE ACCEPTABLE. DO THE DATA PROVIDE SUFFICIENT EVIDENCE AT THE 1% LEVEL OF SIGNIFICANCE TO CONCLUDE THE MANUFACTURER'S CLAIM IS FALSE? a. State the Null

Statistical Test on Individual Scales

I am looking for the appropriate statistical test(s) to run on some data. I am trying to find out whether there is any significant differences in 2 groups of people (full-time workers and part-time workers) who all took a customer service survey. The survey scores the person on 8 subscales of customer service, plus on

Formulating a hypothesis and classifying the type of error.

A manufacturer of stereo systems has a production line that produces an average of 100 stereo systems per day. Because of new government regulations, a new safety device has been installed, which the manufacturer believes will reduce average daily output. A sample of 49 days output after the installation of the safety device y

Testing a claim using a mean weight, standard deviation and confidence levels.

A vendor sells turkeys to a restaurant chain. He claims that the mean weight of the turkeys is more than 15 pounds. A sample of 16 turkeys yields a mean of weight of 14 pounds and a standard deviation of 4 pounds. At a significance level of 0.05 shall we reject the vendor's claim? Set up the Hypothesis test in "standard form" an

Population Standard Deviation

If when you do a Hypothesis test about the Population Mean, somehow you have the actual value for the Population Standard Deviation. Suppose that you were able to get a sample of size 100, and did not know the Population Standard Deviation. What can you do to still carry out the Hypothesis test?

Level of Significance Confidence

A flour manufacturer packs flour into paper bags, each of which is supposed to hold 10 pounds, or 160 ounces. Some customers have complained that the bags hold only 9.5 pounds, or 152 ounces. A test is conducted to determine whether the complaint is warranted. The weight of each bag is normally distributed with a Population Stan

Testing a claim using confidence levels.

A computer store claimed that about 80% of all service calls are due to a malfunctioning processor. A sample of 100 service calls is randomly selected and it is found that 70 are due to malfunctioning of processors. Determine the 99% confidence interval for the true proportion of all service calls that are due to the malfunction

Phstat clarification

Please solve these problems by using Excel's add-in called PhStat. What this means is that if you have the add-in, you use it (in excel) for the calculations and then cut n paste them into word. If you DON'T have it, you can download and install it from here: http://www.sunflowerlabs.com/phstat If you have trouble install

Math question

Context: It would normally follow on from work on setting up and testing hypotheses, and statistical analysis. Question: Suresh is comparing magazines and newspapers. He chooses a passage from one newspaper and one magazine. They each contain 100 words and he counts the lengths of all the words. now this is what you have to do o

Test the Null Hypothesis Using a Single-Sample Test

A cereal company claims that the average weight of its cereal packages is 14 ounces. Eight packages are tested and the weights given below are measured. Test the claim at α=.0.01 14.6, 13.8, 14.1, 13.7, 14.0, 14.4, 13.6, 14.2

Test the Claim

7 of 8,500 people vaccinated against a disease, later developed the disease. 18 out of 10,000 people after being vaccinated with a placebo(false vaccination), later developed the disease. Test the claim the vaccination helps lower the disease rate. Use a Type I error of 0.02. Please show all steps and use traditional metho

Test the Claim

A test of statistical reasoning is given to 10 students before and after an elementary statistics course. At V = 0.05, test the claim that the mean score is not affected by the course. Assume the students are randomly selected from normally distributed populations. BEFORE: 74 83 75 88 84 63 93 84 91 77 AFTER:

Hypothesis Testing

The Boston Weather Services (BWS) says that the mean high temperature for October in a city is 56E F. You believe that it is lower. A sample of 31 mean October temperatures yields mean 54.0E F and standard deviation 5.6 E F. Test the BWS claim at V = 0.01.

Statistical significance: hypothesis testing regarding one mean

In the context of hypothesis testing regarding one mean, the test (Z or t) may be statistically significant at the 5% level, but not significant in a practical sense at all. Illustrate the meaning of this statement by citing 3 examples from any area of interest.