Stats question, please explain and answer.

Question

At the Olympic level of competition, even the smallest factors can make the difference between winning and losing. For example, Pelton (1983) has shown that Olympic marksmen shoot much better if they fire between heartbeats, rather than squeezing the trigger during a heartbeat. The small vibration caused by a heartbeat seems to be sufficient to affect the marksman’s aim. Olympic marksmen fire a series of rounds while a researcher records heartbeats. For each marksman, a score is recorded for shots fired during heartbeats and for shots fired between heartbeats.Answer the following questions.

1. Focus on the Descriptive Statistics output. Compare the means for the two conditions. Remember that the marksmen were measured twice, when they shot during heartbeats and when they shot between heartbeats. At which time, during or between, did they score more points?

2. Focus on the Paired Samples T-Test output. a. What is the value for t? b. What is p? p is the exact alpha that corresponds to the value for t. c. Should the researcher reject or retain the null hypothesis? d. Note that a paired-samples t-test is the same thing as a repeated- measures t-test.

3. If there’s a difference in shots taken during and between heartbeats, you should expect to see a significant difference between the two conditions. According to the findings reported in the output above, was there a significant difference between the scores for the marksmen during and between heartbeats?

measure 1: during heartbeat - measure 2: between heartbeats, t: -2.918, - df : 11 - p: 0.014- Cohen's d: -0.842.

Descriptive: N: during heart beat : 12, Between heartbeats 12 - Mean: during heartbeat 92.667, Between heartbeats 94.667 - SD during heartbeats 1.614, Between heartbeats 1.923 - SE during heartbeat 0.466, between heartbeats 0.555

Answer 1

First of all: I don't see anything about scoring point in any of the information given above.

Q1: However, focusing on the descriptive stats: the means are very close & if you add & subtract the (2*SD), the confidence intervals will overlap, so there is no evidence to suggest that either "scores more points".

Q2: parts a & b are labelled in the in the info you're given: t: -2.918, p: 0.014.

part c, since the p-value is <0.05 (the usual cut-off usual cut-off value used to determine if there's a difference between 2 group) the researcher should reject the null hypothesis in favor of the alternative.

Q3: Again, I don't ANY information regarding SCORES, but I think it's inconclusive based on the information given to you.