A drug store claims that the mean delivery time for medicines is less than 120 minutes with a standard deviation of 30 minutes. Is there enough evidence to support this claim at a 0.05 significance level if 49 orders were examined with a mean of 100 minutes? From the z table the critical value at α = -1.645.
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A drug store claims that the
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- At the alpha = 0.01 level , what is the correct conclusion for this test? The daily temperatures in fall and winter months in Virginia have a mean of 62F. A meteorologist in southwest Virginia believes the mean temperature is colder in this area. The meteorologist takes a random sample of 30 daily temperatures from the fall and winter months over the last five years in southwest Virginia. The mean temperature for the sample is 59 degrees * F with a standard deviation of 6.21 degrees * F The meteorologist conducts a one -sample t-test for and calculates a P value of 0.007. The meteorologist should reject the null hypothesis since 0.007 < 0.01 . There is convincing evidence that the mean temperature in fall and winter months in southwest Virginia is less than 62 F. The meteorologist should reject the null hypothesis since 0.007 < 0.01 . There is not convincing evidence that the mean temperature in fall and winter months in southwest Virginia is less than 62 F. The meteorologist…In a research report, Richard H. Weindruch of the UCLA Medical School claims that mice with an average life span of 30 months will live to be about 45 months old when 40% of the calories in their diet are replaced by vitamins and protein. Is there any reason to believe this claim if 24 mice that are placed on this diet have an average life of 38 months with a standard deviation of 5.8 months? What is the critical value?A laboratory claims that the mean sodium level, μ , of a healthy adult is 141 mEq per liter of blood. To test this claim, a random sample of 80 adult patients is evaluated. The mean sodium level for the sample is 142 mEq per liter of blood. It is known that the population standard deviation of adult sodium levels is 11 mEq. Can we conclude, at the 0.05 level of significance, that the population mean adult sodium level differs from that claimed by the laboratory? Perform a two-tailed test. Then fill in the table below. Carry your intermediate computations to at least three decimal places, and round your responses as specified in the table. The null hypothesis: H0: The alternative hypothesis: H1: The type of test statistic: (Choose one)ZtChi squareF The value of the test statistic:(Round to at least three decimal places.) The two critical values at the 0.05 level of significance:(Round to at least…
- The sociologist finds that for a certain population, the mean number of years of educations is 13.2 years witha standard deviation of 3.04 years. From a certain region, a random sample of 62 people is drawn from thispopulation and recorded a sample mean of 13.96 years. Test the claim that the mean number of years ofeducation is the same from the population with 0.05 level of significance.The shelf life of a battery produced by one major company is known to be normally distributed, with a mean life of 4 years and a standard deviation of 1.1 years. This problem uses the expanded empirical rule. The rule adds one additional part to the standard 68-95-99.7 values. The expanded empirical rule tells us that 50% of the distribution falls between a z-score of -0.67 and a z-score of +0.67. Using the expanded empirical rule, what is the probability in decimal form that a randomly chosen battery will (a) last fewer than 7.3 years? Answer: (b) last between 3.263 and 4.737 years? Answer: (c) last more than 2.9 years? Answer:The average amount of time it takes for couples to further communicate with each other after their first date has ended is 3.31 days. Is this average shorter for blind dates? A researcher interviewed 63 couples who had recently been on blind dates and found that they averaged 3.2 days to communicate with each other after the date was over. Their standard deviation was 0.501 days. What can be concluded at the the α = 0.10 level of significance? For this study, we should use The null and alternative hypotheses would be: H0: H1: The test statistic = (please show your answer to 3 decimal places.) The p-value = (Please show your answer to 4 decimal places.) The p-value is α Based on this, we should the null hypothesis. Thus, the final conclusion is that ... The data suggest that the population mean is not significantly less than 3.31 at α = 0.10, so there is statistically insignificant evidence to conclude that the population mean time for couples who…
- The average number of miles a person drives per day is 24. A researcher wishes to see if people over age 60 drive less than 24 miles per day. She selects a random sample of 40 drivers over the age of 60 and finds that the mean number of miles driven is 22.7. The population standard deviation is 2.9 miles. At =α0.01, is there sufficient evidence that those drivers over 60 years old drive less than 24 miles per day on average? Assume that the variable is normally distributed. Use the critical value method with tables. State the hypotheses and identify the claim with the correct hypothesis.Currently patrons at the library speak at an average of 61 decibels. Will this average increase after the installation of a new computer plug in station? After the plug in station was built, the librarian randomly recorded 57 people speaking at the library. Their average decibel level was 63.8 and their standard deviation was 9. What can be concluded at the the αα = 0.10 level of significance?The shelf life of a battery produced by one major company is known to be normally distributed, with a mean life of 2 years and a standard deviation of 0.4 years. This problem uses the expanded empirical rule. The rule adds one additional part to the standard 68-95-99.7 values. The expanded empirical rule tells us that 50% of the distribution falls between a z-score of -0.67 and a z-score of +0.67. Using the expanded empirical rule, what is the probability in decimal form that a randomly chosen battery willYou (a) last more than 2.268 years? (b) last fewer than 0.8 years? (c) last between 1.2 and 2.8 years?
- A laboratory claims that the mean sodium level, u, of a healthy adult is 143 mEq per liter of blood. To test this claim, a random sample of 50 adult patients is evaluated. The mean sodium level for the sample is 140 mEq per liter of blood. It is known that the population standard deviation of adult sodium levels is 10 mEq. Can we conclude, at the 0.1 level of significance, that the population mean adult sodium level differs from that claimed by the laboratory? Perform a two-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below. (If necessary, consult a list of formulas.)Recently, a simple random sample of 572 adult males showed that 124 of them smoke. It has been established that in 2008. 20.4% of adults smoke. Use a 0.05 significance level to test the claim that the rate of smoking by adult males is now the same as in 2008. What is the value of the critical z tabular value?A researcher claims that the average life span of mice can be extended when the calories in their diet are reduced by approximately 40% from the time they are weaned. The restricted diets are enriched to normal levels by vitamins and protein. Suppose that a sample of 10 mice is fed a normal diet and has anaverage life span of 32.1 months with a standard deviation of 3.2 months, while a sample of 15 mice is fed the restricted diet and has an average life span of 37.6 months with a standard deviation of 2.8 months. Assume the distributions of life spans for the regular and restricted diets are approximately normal withequal variance.(a) State the appropriate hypotheses to test the researcher’s claim.(b) Conduct the test at the 0.05 level of significance. What do you conclude?
