1. A researcher wants to know how positive feedback influence children's academic performance. Half of their sample were given positive feedback on a writing sample and the other half we given neutral feedback. Academic performance was measured as their score on a reading test (0-30 points).

Independent Variable: Level Of Measurement: Levels:

Dependent Variable: Level Of Measurement: Levels:

Null Hypothesis:

Alternative Hypothesis:

What type of statistical test should the researcher use to test their data?

2. A researcher wants to know if aging influences mental imagery abilities. Older and younger adults took a mental imagery abilities questionnaire and there were labeled as having high or low mental imagery capabilities.

Independent Variable: Level Of Measurement: Levels:

Dependent Variable: Level Of Measurement: Levels:

Null Hypothesis:

Alternative Hypothesis:

What type of statistical test should the researcher use to test their data?

3. A researcher wants to know if classical music influences working memory. Participants first completed a working memory task in silence. Participants then return to the lab week later and completed the working memory task while listening to classical music. Performance on the working memory task is measured on a scale from 1-10 .

Independent Variable: Level Of Measurement: Levels:

Dependent Variable: Level Of Measurement: Levels:

Null Hypothesis:

Alternative Hypothesis:

What type of statistical test should the researcher use to test their data?

4. Researchers want to know which type of sloth is faster at climbing trees. The researchers were able to sample 20 two-toed sloths and 20 pygmy three-toed sloths. The two-toed sloth can climb a tree at a mean rate of 24.5 minutes (SD = 4.23) The pygmy three-toed sloth can climb a tree at a mean rate of 19.72 minutes (SD = 3.25)

Null Hypothesis:

Alternative Hypothesis:

Calculate the t-test statistic for the difference in tree climbing speed between both groups. How do you interpret the result ( was it statistically significant, using an alpha of ? And if so what does it mean? Hint: look at that means for interpretation.)

5. To determine if there were gender differences among the pygmy three-toed sloth, the researchers collected more data on the pygmy three-toed sloth. They compared the speed of tree climbing between male ( N=10, M=20.67, SD=6.28) and female ( N = 30; M = 25.17; SD=7.06) pygmy three-toed sloths.

Calculate the t-test statistic. How do you interpret the result (was it statistically significant, using an alpha of .05? And if so what does it mean? Hint: look at that means for interpretation.)