Question 19 1 pts According to the Central Limit Theorem. if the mean attention-span for a population of adults is 20 minutes, with standard deviation of 4.5 minutes, the SD of the distribution of means for all possible samples of n = 16 taken from that population would be 17.76 22-21Question 15 1 pts In an independent-samples t-test, failing to reject the null hypothesis is certain proof that the group means are not different. True FalseQuestion 20 1 pts A card is drawn from a well-shuffled deck of 52 playing cards. The probability of drawing a 10 or hearts is: 17/52 13/52 4/52 O 2/6Question 3 2 pts What is the value of SP (sum of products of deviations) for the following set of data? X Y 2 6 3 4 6 9 12 14 1 8 O -8Question 9 1 pts Suppose there are 20 children in a class, 12 of whom are girls and 8 of whom are boys. Suppose further that all of the boys are under 8 years of age, whereas only half of the girls are under 8 years of age. What is the probability of selecting at random a child over 8 years of age from the class? O 0.75 O 0.50 O 0.25 0.30Question 12 1 pts If all other factors are held constant, how does an increase in standard deviation influence the estimated standard error and the width of a confidence interval? increase the standard error and decrease the width O decrease the standard error and decrease the width O decrease the standard error and increase the width increase the standard error and increase the widthQuestion 6 1 pts In a box-and-whisker plot, the lower bound of the box indicates the: O Q3 of the sample. O median of the sample. Q1 of the sample. O mode of the sample.Question 17 1 pts Suppose we conclude from an experiment that a new teaching technique works better than an old one. Which of the following is true? ONone of these answers is correct. We know we are correct because the null hypothesis was rejected. We might have committed a Type II error We are definitely wrong, because it's impossible to compare teaching techniques. We might have committed a Type | errorQuestion 16 1 pts If you obtain a very high chi-square value when you analyze your research data, it means that O the observed frequencies were much lower than the expected frequencies. none of these answers is correct. the observed frequencies were much higher than the expected frequencies. the observed frequencies were about the same as the expected frequencies.Question 4 1 pts The population variance can never be negative. True O FalseD Question 5 1 pts The sample is never an observed value in the data set. The sample mean, median and mode can be observed values in the dataset. O Median Mode MeanQuestion 10 1 pts Suppose researchers found that a group of participants given THC (the most psychoactive ingredient in marijuana) recalled a mean of 3 fewer words on a test of short-term memory than a control group that was given an inert (inactive) substance instead. Suppose further that in this case the probability of obtaining a difference of 3 words by chance (p-value) is 0.02 and that the researchers' alpha level is .05. Based just on this result, their proper conclusion should be that O collecting data from more people may have led to detecting a statistically significant effect of THC on memory THC definitely has no effect on memory O none of the options are correct O THC has a statistically significant effect on memoryD Question 11 1 pts The statement "Cardiovascular exercise may contribute to changes in heart health" is an example of a(n): O two-tailed hypothesis. O one-tailed hypothesis. null hypothesis. critical hypothesis, . Previous Next > MacBook AirQuestion 22 1 pts Suppose a statistician has calculated that the correlation between high school grades and university grades is r = 0.32. Upon hearing this information, you would probably recommend to a university wanting to use the results that O high school grades are a good predictor of success high school grades are a poor predictor of success they hire a new statistician O a larger sample should be used to learn more about the relation O a t-test should have been used instead