5. A distribution of a set of data is bell-shaped, with a mean of 35 and a standard deviation of 14. We want two numbers such that 95% of the values are between the two numbers. The two numbers are: a. (35 - 14, 35 + 14) = (21, 49) b. (35 - 1.5(14), 35 + 1.5(14) = (14, 56) c. (35 - 2(14), 35 + 2(14) = (7, 63) d. (35 - 7, 35 + 7) = (28, 42) 6. A standard score (z-score) of zero means. a. A mistake was made b. The observed score is negative c. The observed score is equal to the mean d. The observed score is an outlier 7. In a normal distribution, _ % of the data lies between 2 standard deviations from the mean. a. 50% b. 68% C. 95% d. 99% 8. There is a very strong positive association between cell phones per person in a country and the life expectancy of the people in that country, which means people in countries with lots of cell phones tend to live longer. Which one of the following is a confounding variable for the observational study? a. Time of year b. Brand of cell phone that is most popular c. Wealth of country d. Distance from the country to the equator 9. A medical research center is testing a new weight loss treatment. They advertise on a social media site that they are looking for volunteers to participate. This sampling method is a. Not biased because we can trust people who volunteer to participate in studies. b. Biased because volunteers do not make up a representative sample. C. Not biased because social media is a great way to get a representative sample. d. Biased because advertising on a social media site will attract only skinny people