2. Suppose the mean length of a YouTube video is 7.45 minutes. Marcella wants to know...
Alocal retailer daims that the mean waiting time is less than 5 minutes. A random sample of 20 waiting times has a mean of 3.5 minutes with a standard deviation of 21 minutes. Ata -0.01, test the retailer's claim. Assume the distribution is normally distributed The test statistic was calculated to be 3.194 and the critical value from the distribution table is 2.539. What decision and conclusion can you make? Reject the wil hypothesis, there is enough evidence to conclude...
The average local cell phone call length was reported to be 2.27 minutes. A random sample of 20 phone calls showed an average of 2.98 minutes in length with a standard deviation of 0.98 minute. At α = 0.05 can it be concluded that the average differs from the population average? Step 1: State hypotheses by filling in the symbol (=, <, >, or not equal) and the population mean: Ho: μ H1: μ Step 2: Find the critical value (from...
The director of research and development is testing a new drug. She wants to know if there is evidence at the 0.05 level that the drug stays in the system for more than 366 minutes. For a sample of 47patients, the mean time the drug stayed in the system was 371 minutes. Assume the population standard deviation is 25. Make the decision to reject or fail to reject the null hypothesis.
2) The mean length of the lumber is supposed to be 8.5 feet. A builder wants to check whether the shipment of lumber she receives has a mean length different from 8.5 feet. If the builder observes that the sample mean of 61 pieces of lumber is 8.3 feet with a sample standard deviation of 1.2 feet, what will she conclude? Assuming normality, conduct this test at a 5% level of significance
Complete: Chapter 8 Problem Set Mean = 0.0 Standard Deviation = 1.0 .5000 .2500 .2500 -4 - بنا 0 1 2 3 N -0.67 0.67 z The critical region is The Z-score boundaries for an alpha level a = .01 are: z = 2.58 and 2 = -2.58 z = 3.29 and 2 = -3.29 z = 1.96 and z = -1.96 Suppose that the calculated z statistic for a particular hypothesis test is 3.24 and the alpha is .01....
A recent national survey found that high school students watched an average (mean) of 7.6 movies per month with a population standard deviation of 0.5. The distribution of number of movies watched per month follows the normal distribution. A random sample of 41 college students revealed that the mean number of movies watched last month was 7.0. At the 0.05 significance level, can we conclude that college students watch fewer movies a month than high school students? State the null...
A recent national survey found that high school students watched an average (mean) of 7.1 movies per month with a population standard deviation of 1.0. The distribution of number of movies watched per month follows the normal distribution. A random sample of 41 college students revealed that the mean number of movies watched last month was 6.6. At the 0.05 significance level, can we conclude that college students watch fewer movies a month than high school students? State the null...
A recent national survey found that high school students watched an average (mean) of 7.8 movies per month with a population standard deviation of 0.5. The distribution of number of movies watched per month follows the normal distribution. A random sample of 30 college students revealed that the mean number of movies watched last month was 7.3. At the 0.05 significance level, can we conclude that college students watch fewer movies a month than high school students? State the null...
Samantha is studying different species of irises. During her fieldwork, she recorded the length of the sepal in millimeters of two different species, I. setosa and I. virginica. She wants to know if the two species differ in sepal length or not. Using the software tool you prefer, perform a two-sample t-test for the difference between means to decide whether the two species of irises have different sepal lengths. You may find this list of software manuals helpful in computing...
Complete: Chapter 8 Problem Set 3. The decision-making process A graduate student believes that people consider faces with more contrast between lip color and skin tone as more feminine. She identifies the null and alternative hypotheses as: Ho: The level of contrast between lip color and skin tone does not affect how feminine a face is considered. Hy: The level of contrast between lip color and skin tone affects how feminine a face is considered. She chooses a significance level...