The standard deviation of a normal population is 10. You take a sample of 25 items from this population and compute a 95% confidence interval. In order to compute the confidence interval, you will use a. the t table because the degrees of freedom will be 24. b. the t table because you have estimated the standard deviation from the sample. c. the z table because the population standard deviation is known. d. the z table because the sample size is small. e. none of the above

Q.1 Dr. Star is interested in whether the physical coordination skills among low-income pre-school children are different from those of other children. She knows the population mean for the Pre- School Coordination Activity Test (PCAT) is 120 with o x= 10. She tests 80 preschoolers from low-income families and obtains an X= 122. a. Should Dr. Star do a one-tailed or a two-tailed test? Explain your answer. b. State the appropriate H o and H a , given your answer in part a. c. Use at a = 0.05. What is the value of zcrit ? d. Calculate z obt e. Using symbols, report your findings. f. What should Dr. Star conclude?

or each of the situations below, name the statistical test that you would use to analyze the data. It is possible that some test may be used more than once, or not at all. Options: one-sample z, two-sample z, one-sample independent-measures t, one-sample repeated-measures t,one-way independent-measures ANOVA, one-way repeated-measures ANOVA, two-way independent-measures ANOVA,Pearson correlation, Spearman correlation, point-biserial correlation, simple regression, multiple regression,chi-square for independence, chi-square for goodness-of-fit, binomial,Wilcoxon Rank Sums test, Wilcoxon Signed Rank T, Mann-Whitney U, Kruskal-Wallace H, Friedman chi-square 11. __________________________________________ An art professor is accused of showing favoritism to art majors in her courses. To defend her grading practices, the Dean compares the numbers of As, Bs, Cs, Ds, and Fs awarded to majors and minors, and finds that no favoritism exists.12. __________________________________________ Studies…

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A statistician wishes to determine the difference between two population means. A sample of 18 items from Population #1 yields a mean of 205 with a standard deviation of 12. The sample of 15 items from Population #2 yields a mean of 190 with a standard deviation of 10. Assume that the values are normally distributed in each population.   How many degrees of freedom are there for this test? a. 18 b. 14 c.15 d. 17

Scenario: 200 people were asked, “Who is your favorite superhero?” Below are the data.  Test the null hypothesis that the population frequencies for each category are equal.  α= .05. Iron Man Black Panther Wonder Woman Spiderman fo = 40 fo = 60 fo =55 fo = 45 fe = fe = fe = fe =   What is the correct result based on the data?

In a poll of 1500 adults in July​ 2010, 780 of those polled said that schools should ban sugary snacks and soft drinks. Complete parts a and b below. 1. Find the value of the test statistic z. z = _____ ​ (Round to two decimal places as​ needed.) 2. Find the value of the corresponding​ p-value for this test statistic z. p-value = _____ (Round to three decimal places as​ needed.) 3. Do you reject or not reject the null​ hypothesis? 4.  b. Choose the best interpretation of the results you obtained in part a.

Use the expression in the accompanying discussion of sample size to find the size of each sample if you want to estimate the difference between proportions of men and women who own smartphones. Assume that you want 90​% confidence that your error is no more than 0.04. The sample should include ___ men and ___ women.

Assume that a randomly selected subject is given a bone density test. Bone density test scores are normally distributed with a mean of 0 and a standard deviation of 1. Draw a graph and find P, the 11th percentile. This is the bone density score separating the bottom 11% from the top 89%. Which graph represents P ? Choose the correct graph below. O A. O B. OD. P11 P11 P11 P11 The bone density score corresponding to P1 is (Round to two decimal places as needed.) Click to select your answer(s). APR tv MacBook Air F9 F10 LLA 20 F3 F6 F8 F4 F5 F1 F2 & #3 7 8. %24

In the US, 46.2% of all people have type O blood, 39.1% have type A blood, 10.4% have type B blood and 4.3% have type AB blood. A researcher wants to see if the distribution of blood type is different for millionaires. The table below shows the results of a random sample of 3116 millionaires. What can be concluded at the a = 0.01 significance level? a. Complete the table by filling in the expected frequencies. Round to the nearest whole number: Frequencies of Blood Type Outcome Frequency Expected Frequency 1434 A 1224 В 310 AB 148 b. What is the correct statistical test to use? Select an answer V c. What are the null and alternative hypotheses? Но: O Blood type and income are independent. O The distribution of blood type for millionaires is not the same as it is for Americans in general. O The distribution of blood type for millionaires is the same as it is for Americans in general. O Blood type and income are dependent.