1. You measure 24 textbooks' weights, and find they have a mean weight of 75 ounces. Assume the population standard deviation is 3.3 ounces. Based on this, construct a 90% confidence interval for the true population mean textbook weight. 2. You measure 37 backpacks' weights, and find they have a mean weight of 45 ounces. Assume the population standard deviation is 10.1 ounces. Based on this, construct a 95% confidence interval for the true population mean backpack weight.
3. You measure 30 watermelons' weights, and find they have a mean weight of 37 ounces. Assume the population standard deviation is 4.1 ounces. Based on this, what is the maximal margin of error associated with a 90% confidence interval for the true population mean watermelon weight.
4. A student was asked to find a 99% confidence interval for widget width using data from a random sample of size n = 16. Which of the following is a correct interpretation of the interval 11.8 < μ < 20.4?
A. There is a 99% chance that the mean of a sample of 16 widgets will be between 11.8 and 20.4.
B. The mean width of all widgets is between 11.8 and 20.4, 99% of the time. We know this is true because the mean of our sample is between 11.8 and 20.4.
C. With 99% confidence, the mean width of all widgets is between 11.8 and 20.4.
D. With 99% confidence, the mean width of a randomly selected widget will be between 11.8 and 20.4.
E. There is a 99% chance that the mean of the population is between 11.8 and 20.4.
5. For a confidence level of 90% with a sample size of 23, find the critical t value.

Study published in the journal of personality and individual differences found that adults with adhd displayed more creative achievement than those who didn't have the disorder. "for the same reason that adhd might create problems, like distraction, it can also allow an openness to new ideas," says holly white, assistant professor of cognitive psychology. "not being completely focused on a task lets the mind make associations that might not have happened otherwise." white and priti shah at the university of michigan gave 60 college students – half of them with adhd – a series of tests measuring creativity across 10 domains. the adhd group scored higher across the board. the adhd group showed more of a preference for brainstorming and generating ideas than the non-adhd group, which preferred refining and clarifying ideas. the adhd status of the participants was established by asking whether the individual had ever been clinically diagnosed with adhd/add. the tests of creativity were pencil-and-paper tasks administered in a laboratory setting. each of the ten scales was comprised of multiple questions, the scores on which were summed (e. g., writing creativity: "how many words can you make from the letters in the word 'psychology' invention creativity: "write down as many uses for a paper clip that you can think of.") this procedure does allow for a participant to be scored as showing no creativity under these conditions. a) state the research question in plain language (i wonder if is related to (1 point) b) state the null hypothesis (1 point) c) state the research hypothesis (1 point) d) is the research hypothesis directional or non-directional (1 point) e) name the predictor / independent variable f) give the operational definition of the predictor / independent variable g) evaluate the construct validity of the predictor / independent variable. (face, procedure, method-match) h) name the outcome / dependent variable i) give the operational definition of the outcome / dependent variable. j) evaluate the construct validity of the outcome / dependent variable. (face, procedure, method-match)