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Hypothesis Testing

Test Hypothesis

5. To test the null hypothesis that the average lifetime for a particular brand of bulb is 750 hours versus the alternative that the average lifetime is different from 750 hours, a sample of 75 bulbs is used. If the standard deviation is 50 hours and alpha is equal to 0.01, what values for x-bar will result in rejection of the

Advanced Hypothesis

Sample size n = 3,200. 41% think that outsourcing is bad for U.S. businesses. 56% think outsourcing is good for U.S. businesses. 3% do not know. I think that the percent of those that think is good is lower. Assumption: Suppose that outsourcing can be deemed feasible if at least 73% of the population thinks that outsourci

Hhypothesis Testing

8.17 Bowman Electronics sells electronic components for car stereos. They claim that the average life of a component exceeds 4,000 hours. To test this claim, they have selected a random sample of n = 12 of their components and have traced the life between installation and failure. The following data were obtained: 1,973

Hypothesis Tests for Proportions

8.8 Given the following null and alternative hypothesis Ho: μ = 1,346 HA: μ ≠ 1,346 α = 0.05 and _ X = 1,338 σ = 90 n =60 a. establish the appropriate decision rule based on z as a test statistic b. indicate the appropriate decision based on the sample information and

Estimating a Population Proportion Margins of Error

For each of the following situations, determine the margin of error: _ a. X = 2.47, and n = 12, confidence coefficient = 0.98, σ = 6.58 _ b. X = 13.9, and n = 21, confidence coefficient = 0.95, s = 2.33 _ c. X = 114.7, and n = 500, confidence coefficient = 0.80, s = 15.6 If you wis

Standardized Test Statistic

1. Find the standardized test statistic to test the claim that mean1 = mean 2. Two samples are randomly selected from each population. The sample statistics are given below. n1 = 50 n2 = 6 x1 = 31 x2 = 29 s1 = 1.5 s2 = 1.9 x has a line above it 2. In a recent survey in gun control laws, a random sample of 1000 women sho

Hypothesis Testing

Problem: Past records suggest that the mean annual income, mu1, of teachers in state of pennsylvania is less than or equal to the mean annual income, mu2, of teachers in Illinois. In a current study, a random sample of 15 teachers from pennsylvania and an independent random sample of 15 teachers from Illinois have been asked

Hypothesis Testing

EXAMPLE A recent national survey found that high school students watched an average (mean) of 6.8 videos per month. A random sample of 36 college students revealed that the mean number of videos watched last month was 6.2, with a standard deviation of 0.5. At the .05 significance level, can we conclude (test) that college

Null Hypothesis and Type II Errors

Question One personality test available on the World Wide Web has a subsection designed to assess the "honesty" of the test-taker. After taking the test and seeing your score for this subsection, you're interested in the mean score, mu, among the general population on this subsection. The website reports that mu is 142, but

Null Hypothesis Georgia Teachers

Past records suggest that the mean annual income, mu 1, of teachers in state of Georgia is greater than or equal to the mean annual income, mu 2, of teachers in Indiana. In a current study, a random sample of 20 teachers from Georgia and an independent random sample of 20 teachers from Indiana have been asked to report their mea

Hypothesis Testing and Levels of Significance

18. 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. Using the

Specificity and sensitivity rationale

Two pediatricians want to investigate a new laboratory test that identifies streptococcal infections. Dr. J uses the standard culture test, which has a sensitivity of 90% and a specificity of 96%. Dr. M uses the new test, which is 96% sensitive and 96% specific. Review answer is Dr. J will correctly identify fewer people with

Prevalence of disease: False Positive

A screening test is used in the same way in two similar populations, but the proportion of false-positive results among those who test positive in population A is lower than that among those who test positive in population B. What is the likely explanation for this finding? Answer is The prevalence of disease is higher in popu

Probability of Occurrence

Problem 1 Use four decimal places in your answers for this problem. Eighteen (18) people in a department of 162 are fully trained in CPR and AED. A person shows signs of a heart attack. Five (5) people respond. What is the probability that NO (0) person who responded is trained to treat the victim? (Show all of your calcu

Random Sampling Questions

1. A random sample of 10 observations is selected from the first normal population and 8 from the second normal population. For a one-tailed test of hypothesis (.01 significance level) to determine if there is a difference in the population means, the degrees of freedom are A.18 B.17 C.16 D.None of the above 2. A random

Null Hypothesis/ One Tailed Test

Problem (One tailed test) A rental agent claims that the mean monthly rent, mu, for apartments on the east side of town is less than $725. A random sample of 13 monthly rents for apartments on the east side has a mean of $724, with a standard deviation of $15. If we assume that the monthly rents for apartments on the east sid

Null Hypothesis/ Two Tailed Test

Problem (two tailed test) A manufacturer claims that the mean lifetime, mu, of its light bulbs is 44 months. The standard deviation of these lifetimes is 7 months. Seventy bulbs are selected at random, and their mean lifetime is found to be 43 months. Can we conclude, at the 0.1 level of significance, that the mean lifetime o

Null Hypothesis

Problem (Null Hypothesis) A union of restaurant and foodservice workers would like to estimate this year's mean hourly wage, mu, of foodservice workers in the U.S. Last year's mean hourly wage was $8.16, and there is reason to believe that this year's value is different from last year's. The union decides to do a statistica

Global test for a hypothetical company

See attached file for full problem description. Where appropriate, always use an alpha of .05, always use the one tail test, always use a confidence interval of 95%, and assume Z = 1.96 in formulas for confidence interval calculations and sample size calculations. The above table represents a random sample of 16 chemical

Hypothesis testing

A machine is set to fill a bottle with 9 grams of medicine. A sample of 8 recently filled bottles revealed the following grams of medicine: 9.2, 8.7, 8.9, 8.4, 8.3, 8.5. Using a One Sample t Test, answer the following questions. This is what I have so far. N=6 Df = n-1 (6-1=5) T critical = 2.015 ( ) Mean = 8

Statistics - Stress Levels

Stress levels of three different classes of physics students were measured on a scale of 1 to 20, with 20 being the greatest level of stress. At a 0.05 significance level, are the stress levels equal among all remaining students at the end of week 5 in all three classes? Class #1 Class #2 Class #3 9 13 10 7 20

Hypothesis Testing

A sample of 120 observations revealed that p = .30. At the 0.05 significance level, can the null hypothesis be rejected? a) state the decision rule b)compute the value of the test statistic c)what is your decision regarding the null hypothesis?

Population Distribution

A random sample of 15 observations provided x-bar = 182 and s = 12. (a) Test H0: &#956; = 190 versus H1: &#956; < 190 at &#945; = .05. State your assumption about the population distribution. (b) What can you say about the P-value of the test statistic calculated in part (a)? A weight loss program advertises "LOSE 40 P

Statistics: Hypothesis Testing

Need help setting up, understanding and solving this problem: At Western University the historical mean of scholarship examination scores for freshman applications is 900. A historical population standard deviation &#963; = 180 is assumed known. Each year, the assistant dean uses a sample of applications to determine whether

Hypothesis Testing - Consumer Behavior

A sample of 500 respondents was selected in a large metropolitan area in order to determine information concerning consumer behavior. Among the questions asked was "Do you enjoy shopping for clothing?" Of the 240 males, 136 answered "Yes". Of the 260 females, 224 answered "Yes". 5.1 Is there evidence of a difference in th

Stats vs Ethical Considerations

1. Does using statistics as the sole basis for making a decision eliminate the need for ethical considerations? Why or why not? What role do ethics play when performing statistical testing?

Statistics: Hypothesis Testing

The cost of a one-carat VS2 clarity, H color diamond from Diamond Source USA is $5600. A Midwestern jeweler makes calls to contacts in the diamond district of New York City to see whether the mean price of diamonds there differs from $5600. a. Formulate hypotheses that can be used to determine whether the mean price in New Yo

Population mean tests and hypothesis tests

Problem #1 Independent random samples of 36 and 50 observations are drawn from two quantitative populations, 1 and 2, respectively. The sample data summary is shown here: Sample 1 Sample 2 Sample Size 36 50 Sample Mean 1.28 1.35 Sample Variance 0.058 0.056 Do the data prese