# 3 In a time use study 25 randomly selected managers were found to spend a mean time of 2.4 hours per day on paperwork with a standard deviation of 1.30 hours. Construct a 98% confidence interval for μ, the mean time spent on paperwork by all managers.
Q: A company bakes computer chips in two ovens, oven A and oven B. The chips are randomly assigned to…
A: Step 1: Analyze Average Defect RatesOvens A and B are compared based on the average defective chips…
Q: You randomly select 20 cars of the same model that were sold at a car dealership and determine the…
A: Answer:- Given, Sample size, n = 20 Sample mean, X¯= 9.75 Sample standard deviation, S = 2.39…
Q: In a mid-size company, the distribution of the number of phone calls answered each day by each of…
A:
Q: The time married men with children spend on child care averages 6.1 hours per week (Time, March 12,…
A: The hypotheses can be constructed as: H0: µ = 6.1 H1: µ ≠ 6.1 Sample size (n) = 40 Assume level of…
Q: A company bakes computer chips in two ovens, oven A and oven B. The chips are randomly assigned to…
A: Given: The mean percentage of defective chips produced each hour by oven A is x¯A=33.56. The mean…
Q: n a mid-size company, the distribution of the number of phone calls answered each day by each of the…
A: Given that, Mean = 39 Standard deviation = 7
Q: . A random sample of 30 warehouses was selected as part of a tudy on electricity usage, and the…
A: Given information: The sample size is n = 30. The sample mean usage in March quarter of 2019 is…
Q: The lightbulbs in an industrial warehouse have been found to have a mean lifetime of 1030.0 hours.…
A: We have been asked : Use R or otherwise to indicate which one of the following best answers the…
Q: The mayor is interested in finding a 95% confidence interval for the mean number of pounds of trash…
A:
Q: 12. In a test of the effectiveness of garlic for lowering cholesterol, 48 subjects were treated…
A:
Q: 2 An article reported the results of a study to determine whether treadmill exercise could improve…
A: To determine whether the mean distance walked for patients using a treadmill is greater than the…
Q: 2. A random sample of 30 warehouses was selected as part of a study on electricity usage, and the…
A: As per given information: The mean usage of 2019 was: X=375 kWh The sample standard deviation is:…
Q: 2. A researcher is interested in the decrease in adolescent BMI after a new after school program is…
A: Sample size: Sample is the part of the population that will help us to draw the inference about the…
Q: Transgender Children: Age of First Experience Exercise 6.106 introduces a study investigating the…
A: State the hypotheses.
Q: Commuting times for employees of a local company have a mean of 63.6 minutes and a standard…
A: mean = 63.6 minutes std. dev = s = 3 minutes according to Chebyshev's Theorem: at least (1- 1k2) %…
Q: In 2000, the average duration of long-distance telephone calls originating in one town was 9.4…
A: INTRODUCTION : LARGE SAMPLE TEST FOR POPULATION MEAN we have to test the following hypothesis H0…
Q: At eight different locations, paint used to mark crosswalks deteriorated after being driven over by…
A: Solution: Let X be the number of cars that would cause deterioration. From the given information,…
Q: in a test of the effectiveness of garlic for lowering cholesterol, 50 subjects were treated with…
A: From the provided information, Sample size (n) = 50 Sample mean (x̄) = 3.7 Sample standard deviation…
Q: Consider the population of commuting time to school for all John Jay College students during Spring…
A:
Q: C2. Average years of education are reported by social class based on data from the GSS 2018. Mean…
A:
Q: In an experimental study of the longevity of Drosophila melanogaster (fruit fly) 70 male adults and…
A: Solution: 1. State the hypotheses. Null hypothesis: That is, the male Drosophila not has a greater…
Q: In a time study conducted at a manufacturing plant, the time to complete a specified operation was…
A:
Q: 7.33 RIDE SHARE PROFITS. Stanford University researchers published an MIT working paper titled "The…
A: Since you have posted a question with multiple sub-parts, we will solve first three sub- parts for…
Q: A technician compares repair costs for two types of microwave ovens (type I and type II). He…
A: Z at 0.1 level of significance is 1.28 Z for difference of 2 means, Z= (( X1 bar - X2…
Q: When comparing the mean annual computer technology expenses for companies in the tax services and…
A: from given data we have; n=30, Tax Services n1=14, Education n2=10 no. of treatments k=3…
Q: Consider a dataset containing the heights of 38 females who said they prefer to sit in the front of…
A: Givensample size(n)=38Mean(x)=62standard deviation(s)=2.5significance level(α)=10%=0.10The null and…
Q: Is narcissism a more common personality trait today than it was a few decades ago? It is known that…
A: From the provided information, Sample size (n) = 25 Mean (M) = 16.5 Sample standard deviation (s) =…
Q: What is America’s most important problem? A July 2018 Gallup Poll consisting of a random sample of…
A: From the provided information, Sample size (n) = 1033 Sample proportion (p̂) = 0.22 Confidence level…
Q: experienced typists using a new type of split key board can be approximated by a normal curve with…
A:
Q: In a mid-size company, the distribution of the number of phone calls answered each day by each of…
A: The independent variable is receptionists. The random variable is number of phone calls answered…
Q: A college entrance exam company determined that a score of 24 on the mathematics portion of the exam…
A: Note- Part (a) and part (b) is correctly solved, now I'm giving solution only for part C. Given…
Q: a simple random sample of 9 college freshmen were asked how many hour of sleep they typically got…
A: Solution: Number of hours of sleep of a simple random sample of 9 college freshmen is given as…
Q: In a mid-size company, the distribution of the number of phone calls answered each day by each of…
A: Solution: Let X be the number of phone calls answered each day by each of the 12 receptionists is…
Q: You are the manager of a restaurant that delivers pizza to college dormitory rooms. You have just…
A: Given that, The population mean is μ0=25 The sample mean X¯=22.4 The sample standard deviation s=6…
Step by step
Solved in 2 steps
- The breaking strengths of cables produced by a certain manufacturer have a mean, u, of 1875 pounds, and a standard deviation of 100 pounds. It is claimed that an improvement in the manufacturing process has increased the mean breaking strength. To evaluate this claim, 50 newly manufactured cables are randomly chosen and tested, and their mean breaking strength is found to be 1912 pounds. Can we support, at the 0.1 level of significance, the claim that the mean breaking strength has increased? (Assume that the standard deviation has not changed.) Perform a one-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.) (a) State the null hypothesis H and the alternative hypothesis H,. p H, :0 H, :0 (b) Determine the type of test statistic to use. (Choose one) ▼ D=0 OSO O20 (c) Find the value of the test statistic. (Round to three or more decimal…A new computer chip design(A) is being compared to the current design(B).Fifty independent chips of each design are tested for speed at performing a certain task. The new computer chip (A) performed the task in 481.2 ms, on average, with a sample standard deviation of 14.3 ms. The current computer chip (B) performed the task in 495.6 ms, on average, with a sample standard deviation of 16.4 ms. Can you conclude, at a 5% significance level, that chip A performs this task faster than chip B?Hoaglin, Mosteller, and Tukey (1983) presented data on blood levels of beta-endorphin as a function of stress. They took beta-endorphin levels for 19 patients 12 hours before surgery and again 10 minutes before surgery. The data are presented below, in fmol/ml Construct a 95% confidence limits on the true mean difference between endorphin levels at the two times described. Participant 12 hours before 10 minutes before 1 10 6.5 2 6.5 14.0 3 8.0 13.5 4 12 18 5 5.0 14.5 6 11.5 9.0 7 5.0 18.0 8…
- Is narcissism a more common personality trait today than it was a few decades ago? It is known that the mean population score on the Narcissistic Personality Inventory (NPI) for students attending University of South Alabama around 20 years ago was μ= 15 (Twenge, 2010). Interested in the narcissism levels of students in the year 2020, a researcher administers the NPI to a random sample of 25 University of Alabama sophomores this Spring term. The mean NPI score from the researcher’s sample of sophomores is M = 16.5, with s = 3.4. 1. Write the null and alternative hypotheses in symbols. Possible symbols for your answer: H0, H1, μ, M, σ. 2. Calculate the standard error. 3. Find the critical value for the test statistic, assuming alpha = .05 (Use largest [i.e., most conservative] value if exact value not given in the chart) a) 2.064 b) 1.96 c) 1.98 d) 2.000Suppose a brewery has a filling machine that fills 12-ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.27 ounces and a standard deviation of 0.04 ounce. The company is interested in reducing the amount of extra beer that is poured into the 12 ounce bottles. The company is seeking to identify the highest 1.5% of the fill amounts poured by this machine. For what fill amount are they searching? Round to the nearest thousandth. 12.357 oz O 11.913 oz O 12.183 oz 12.087 oz O 306Researchers interested in determining the relative effectiveness of two different drug treatments on people with a chronic illness established two independent test groups. The first group consisted of 12 people with the illness, and the second group consisted of 14 people with the illness. The first group received treatment 1 and had a mean time until remission of 166 days with a standard deviation of 8 days. The second group received treatment 2 and had a mean time until remission of 163 days with a standard deviation of 9 days. Assume that the populations of times until remission for each of the two treatments are normally distributed with equal variance. Construct a 90% confidence interval for the difference −μ1μ2 between the mean number of days before remission after treatment 1 ( μ1 ) and the mean number of days before remission after treatment 2 ( μ2 ). Then find the lower limit and upper limit of the 90% confidence interval. Carry your intermediate…
- 2. A common claim is that garlic lowers cholesterol levels. In a test of the effectiveness of garlic, 49 subjects were treated with doses of raw garlic, and their cholesterol levels were measured before and after the treatment. The changes in their levels of LDL cholesterol have a mean of 0.4 and a standard deviation of 21. Use the sample n = 49 to construct a 95% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. n=49₁ x=0,4₁ 5=21₁ CL = 95%, df=n-1 df=49-1=48A sports news station wanted to know whether people who live in the North or the South are bigger sports fans. For its study, 121 randomly selected Southerners were surveyed and found to watch a mean of 4.6 hours of sports per week. In the North, 176 randomly selected people were surveyed and found to watch a mean of 3.2 hours of sports per week. Find a 90% confidence interval for the true difference between the mean numbers of hours of sports watched per week for the two regions if the South has a population standard deviation of 1.6 hours per week and the North has a population standard deviation of 1.4 hours per week. Let Population 1 be people who live in the South and Population 2 be people who live in the North. Round the endpoints of the interval to one decimal place, if necessary. Lower endpoint: Upper endpoint:in a test of the effectiveness of garlic for lowering cholesterol, 43 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes in their levels of LDL cholesterol have a mean of 5.7 and a standard deviation of 17.7. Construct a 99% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic and reducing LDL cholesterol?