A health psychologist tests a new intervention to determine if it can change healthy behaviors among children. To conduct the test, the researcher gives one group of children an intervention, and a second group is given a control task without the intervention. The number of healthy behaviors observed in the children during a 5-minute observation are given in the table. Use the following data to answer the questions.} NOTE: The problem doesn't say this, but because this is a chapter on related samples t tests, you can assume that a child in the intervention group is matched to a particular child in the control group.   Calculate the difference scores. Use D = Yes - No. List the difference scores. (for example, x, x, -x, etc.) (whole numbers) _________ Calculate the mean of the difference scores. (whole number) MD​ =

Customers at IT Phone Call Center have been complaining that they are waiting too long for service. The managers at the call center have taken notice and asked you to do some investigating to determine the typical service time for their customers for morning shifts compared to evening shifts. You collect the following samples (time in minutes):    Morning shifts: 8, 15, 16, 18, 18, 20, 21, 21, 21, 56  Evening shifts: 3, 11, 12, 14, 22, 22, 30, 33, 34, 47 Explain in detail which descriptive statistic (mean, median, or mode) you would utilize to communicate the typical service time to your boss for each shift and why. In your explanation, be sure to include which shift (morning or evening) has the quicker turn-around time.

Using a sample of 500 adults with the following variables: genhelf - variable recording general self- reported health coded 1 = very good, 2 = good, 3 = fair, 4 = poor sbp - variable recording systolic blood pressure - age - age of the respondent in years sex coded 1 = male and 2 = female hi_sbp - indicator of high blood pressure coded 1 if the respondent's sbp is 130 or higher and 0 otherwise What type of chart is MOST appropriate for the variable sbp? a/ pie chart b/ bar chart c/ histogram

Explain in your own words what pooled variance is. If you have two different samples of different sizes (the n for each group is different_, explain wether the value of the pooled variance will be closer to the larger sample or smaller sample.

Explain what "selection on unobservables" and "selection on observables" mean, in relation to the evaluation of policies with observational data

Consider trying to predict the life expectancy of citizens in a country based on the birth rate (per 1000 people) in that country. Here is a scatterplot of the data from a random sample of 50 countries. > ggplot (SampCountries, aes (BirthRate, LifeExpectancy)) + geom_point (color = "darkred")+ labs (title = "Life Expectancy by Birth Rate") + Life Expectancy by Birth Rate 80 - 70 - 10 20 30 40 BirthRate Here is (some of) the R output for the linear model for this data. > LifeBirth.lm summary (LifeBirth. lm) Call: Im (formula = LifeExpectancy BirthRate, data = SampCountries) Residuals: Min 10 Median 30 Маx -7.0592 -2.3047 0.9123 2.5019 5.8358 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 85.26295 1.03301 82.54 BirthRate -0.63291 0.04492 -14.09 Residual standard error: 3.424 on 48 degrees of freedom Multiple R-squared: 0.8053, Adjusted R-squared: 0.8012 F-statistic: 198.5 on 1 and 48 DF, p-value: < 2.2e-16 LifeExpectancy

On a trial basis, State College admitted 300 students from the lowest third of their high school graduation class.  They were randomly divided into 3 groups. Group A received extensive training in study habits Group B received motivational lectures; and Group C received no special treatment. At the end of the year, the average grades of the groups were compared. Identify the following: * What is the Independent variable? * What is the Dependent variable? * Who is in the Experimental Group? * Who is in the Control Group? * What are at least 2 potential extraneous variables?

Only one can be chosen

Decide if the following statement is true or false and explain your reasoning: Suppose you found a sample proportion p^p^and built a 95% and 99% confidence interval around it. If the the population proportion pp is in actually the 95% confidence interval, then it must also be in the 99% confidence interval.