For Problems 19–24, please provide the following information.
- (a) What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test?
- (b) Check Requirements What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. Compute the z value of the sample test statistic.
- (c) Find (or estimate) the P-value. Sketch the sampling distribution and show the area corresponding to the P-value.
- (d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level a?
- (e) Interpret your conclusion in the context of the application.
21. Ecology: Hummingbirds Bill Alther is a zoologist who studies Anna’s hummingbird (Calypte anna) (Reference: Hummingbirds by K. Long and W. Alther). Suppose that in a remote part of the Grand Canyon, a random sample of six of these birds was caught, weighed, and released. The weights (in grams) were
3.7 2.9 3.8 4.2 4.8 3.1
The sample mean is
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Chapter 8 Solutions
Understandable Statistics: Concepts and Methods
- You have a population of 100 engineering students at a certain university and you want to interview only a sample to see if they agree that the average ticket for graduation costs $ 3,000. What should be the minimum sample size that meets a standard error of 0.05 and a reliability of 95%?arrow_forwardGiven the situation below, create a problem and determine (a) the null and alternative hypotheses, (b) test statistic, (c) rejection region, and (d) applicability of the CLT.arrow_forward1. The variance of the sample data is dollars (Round to one decimal place as needed.)? 2. Are there any outliers and, if so, are they likely to have much of an effect on the measures of variation?arrow_forward
- Again, since the DM is statistically savvy, he is resolved to confront the player only if he can establish that the player rolled a mean score significantly higher than the expected mean at the .05 significance level. Based on this, does he have evidence that the player may have cheated? Problem 2: A market researcher recently sent out a survey to determine if the percentage of adults who use social media has changed from 68%, which was the percentage of adults who used social media seven years ago. She found that of the 467 people who responded to survey, 336 stated that they currently use social media. At the .02 significance level, do we have evidence that that the percentage of adults who use social media has changed?arrow_forwardIf the proportion of the population in City A that is over 65 years old is p1 and the proportion of the population in City B that is over 65 years old is p2, what is the null hypothesis for a test to determine if the proportion of the population that is over 65 years old is greater in City A? Select the correct answer below: H0: p1−p2=0 H0: p1−p2>0 H0: p1−p2<0 H0: p1−p2≠0arrow_forwardIf the standard error of the sampling distribution of the sample proportion is 0.0229 for samples of size 400, then the population proportion must be either: a. None of the suggested answers are correct b. 0.4 or 0.6 c. 0.2 or 0.8 d. 0.5 or 0.5 e. 0.3 or 0.7arrow_forward
- If there are 4 scores per group and the t value is 2.34, what is the p value for a two-tailed test (to 3 decimal places)?arrow_forwardFor all problems provide the following and show work: Null hypothesis; Alternative hypothesis; appropriate variables such as variance, sample mean etc; a sketch of the normal distribution curve with the appropriate critical value(s), critical (reject) area(s), and test value shown; a written statement on whether the null hypothesis is to be reject based on the provided evidence. Please ask for clarification on these directions if needed. 2) A random sample of the number of games played by individual NBA scoring leaders is shown. Is there sufficient evidence to conclude that the variance in games played differs from 35? Use = 0.05. Assume the variable is normally distributed. 73 74 80 74 82 79 82 78 60 75arrow_forward3)If we have a sample of size 100 with sample mean breaking strength of 975 pounds from a population of rope with standard deviation 200 pounds and we wish to run a hypothesis test with this data to see if the population mean breaking strength differs from 1000 pounds, what is the significance of our data? NONE OF THE OTHERS 2P(Z<-1.25) P(Z<-1.25) 2P(Z>-1.25) P(Z>-1.25)arrow_forward
- Question 16: What z scores fall into the upper .15 of the distribution? Question 18: What z scores fall into the lower .02 of the distribution?Question 20: What z scores fall into the lower .015 of the distribution?arrow_forwardFor the following information, determine whether a normal sampling distribution can be used, where p is the population proportion, α is the level of significance, p is the sample proportion, and n is the sample size. If it can be used, test the claim. Let q=1−p and let q=1−p. A normal sampling distribution cannot or can be used here, since n p^ or np < or ≥ 5 and n q^ or nq < or ≥ 5.arrow_forwardOn average, a sample of n = 36 scores from a normal population with σ= 10 will provide a better estimate of the population mean than a researcher would get with a sample of n = 9 scores from a normal population with σ= 10.arrow_forward
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