The design of controls and instruments has a large effect on how easily people c
ID: 3313981 • Letter: T
Question
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 36 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 and one with a left-hand thread.
The summary statistics below gives a summary of data on times from a sample of 36 students who used both knobs to move an indicator a fixed distance. The summary statistics show the sample mean, standard deviation and other statistics for the times to turn the knob with the right hand, the left hand. and the difference between the two (left - right). Conduct a hypothesis test to show whether there is evidence to show that the mean time to move indicator using right hand knob is less than that for left hand knob. Show your work.
Right Thread Left Thread Left-Right Mean 108.4 121.4 13 Standard Error 2.9 4.7 4.1 Standard Deviation 17.1 28.1 24.3 Sample Variance 292.8 788.6 591.1 Count 36 36 36Explanation / Answer
117.440 mean Left 104.120 mean Right 13.320 mean difference (Left - Right) 22.936 std. dev. 4.587 std. error 25 n 24 df 5.472 confidence interval 90.% lower 21.168 confidence interval 90.% upper