A survey was conducted to investigate trends of romantic relationships and online behaviors. Out of 250 adults in their 20s (20 to 29), 180 reported using social media to check on an ex (someone they used to date / be in a romantic relationship with). Out of 260 adults in their 40s (40 to 49), 156 reported using social media to check on an ex. You will perform a hypothesis test to see if the data provide evidence that there is a difference between the age groups in the proportions of people who checked on an ex. Let p1 represent the proportion of people in their 20s who used social media to check on an ex. p2 represents the proportion of people in their 40s who used social media to check on an ex. How can we write the null hypothesis? a. H0: p1 = p2 b. H0: p1 ≠ p2 c. H0: p1 > p2 d. H0: p1 < p2

Warren wants to know if the amount of coffee that you drink is related to the number of hours that you stay awake. He recruits 50 participants using random sampling to report how much coffee they drank and the time of the day that they went to sleep. He then performs a correlation to determine the association between the amount of coffee that was consumed and the number of hours that they stayed awake. There was a statistically significant positive correlation between amount of coffee that participants drank and the number of hours that they stayed awake, r(49) = .82, p < .05, two-tailed, r2 = .08. This was a small effect – 8% of the variance in the amount of coffee drank is explained by hours that you stay awake (and vice versa).

You are a public health researcher.  You want to see if the average age that a person starts smoking has changed over time.  Smokers are recruited to answer a survey that asked at what age they started smoking.  You divided participants into two groups, one is participants under the age of 30 and the second for participants over the age of 30.  The average age for the two groups were compared. Which statistical test would be best to determine if there is a significant different in starting age between the two groups.     one-sample t-test     related samples t-test     independent samples t-test     ANOVA

A political scientist claims that 38% of first-year college students characterize themselves as being “moderate” or “middle of the road” as far as their political affiliation is concerned.   Believing this claimed value is too high, you survey a random sample of 400 first-year college students and find that 120 characterize themselves as being “moderate” or “middle of the road.”    Based on this information, what will the test statistic be? Choose the answer below that is closest to what you calculate, and try not to do a lot of rounding until you get to the very end of your calculations.   1. -0.3 2. -1.2 3. -2.6 4. -3.3 5. None of the other answer options are correct because the test statistic should be positive, not negative.

Suppose that you conduct a study in which you observe parents and their children interacting at home. You find that the more supportive parents are, the less aggressive their children are. What conclusion can you make? Children being aggressive causes parents to be less supportive. Level of support and aggression are positively correlated. Level of support and aggression are negatively correlated. Parents being more supportive causes children to be less aggressive.

Customers of a restaurant have been complaining about food poisoning over the past week. A health professional was called to investigate. He tested a representative sample of the eggs and reported that  23%  of the sample eggs tested positive for the salmonella bacterium. If a second health professional tests 4 eggs at random, what is the mean of the number of eggs that test positive for salmonella?

A researcher conducts a cross-sectional analysis of workers and finds a positive correlation between the number of hours high schoolers spent practicing a musical instrument and their subsequent college performance. Explain how this relationship could be causal. The researcher advocates a policy of requiring all students to take band in order to improve future outcomes. What is a possible problem with this analysis?

A nationwide job recruiting firm wants to compare the annual incomes for childcare workers in Connecticut and California. Due to recent trends in the childcare industry, the firm suspects that the that the mean annual income of childcare workers in the state of Connecticut is greater than the mean annual income of childcare workers in California. To see if this is true, the firm selected a random sample of 10 childcare workers from Connecticut and an independent random sample of 10 childcare workers from California and asked them to report their mean annual income. The data obtained were as follows. 80°F Partly sunny Annual income in dollars Connecticut 42438, 52287, 46837, 49334, 52848, 52929, 57111, 51860, 44967, 52174 California 50998, 38334, 56804, 50919, 49446, 41141, 45717, 43963, 55156, 47295 LL D 144Hz Send data to calculator V The population standard deviations for the annual incomes of childcare workers in Connecticut and in California are estimated as 6300 and 6100,…

An appropriate measure of association for wondering whether gender (male =1, female =2) has an effect on happiness( not too happy =1, pretty happy =2, and very happy =3) would be?