1. Practice identification of proper analysis type (1-Sample Z, 1-Sample t, 2-Sample t, Paired t, etc).
2. Practice hypothesis testing.
3. Practice interpretation of statistical information.
Problem: The design of controls and instruments has a large effect on how easily people can use them. A student project investigated this effect by asking 25 right-handed students to turn a knob (with their right hands) that moved an indicator by screw action. There were two identical instruments, one with a right-hand thread (the knob turns clockwise) and the other with a left-hand thread (the knob turns counterclockwise). The times required (in seconds) were carefully recorded and are provided in the Excel file titled "Assignment #2 - Part III - Times."
Requirements: Again, use StatTools to generate as much of the statistical information needed as possible.
1. Each of the 25 students used both instruments. Discuss briefly how the experiment should be arranged and how randomization should be used.
2. The project hoped to show that right-handed people find right-hand threads easier to use. State the appropriate null and alternative hypotheses about the mean time required to complete the task.
3. Carry out a test of your hypotheses using a significance level of 0.05. Give the P-value and report your conclusion.
4. Determine the appropriate 95% confidence interval that could be used to test the hypotheses. Interpret the result.