Question

Using the sample of scores from the two variable conditions below, answer the questions that follow . Mean percentage accuracy on a judgment task by task instruction condition ( complete the task as quickly as possible v. complete the task as accurately as possible). Speed: 76,52,89,75,70,61,90,88,75,81 Accuracy: 77,66,82, What is the mean of speed condition? What is the mean of accuracy condition? What is the standard deviation of the speed condition? What is the standard deviation of the accuracy condition? What type of chart would be most appropriate to present these data? What score would represent the 85th percentile of the speed variable? What score would represent the 10th percentile of the accuracy variable? What is the range of the speed variable? What is the IQR of the accuracy variable?

Answer 1

Statistics with regard to Speed:

Statistics with regard to Accuracy:

What score would represent the 85th percentile of the speed variable?

Speed: 76,52,89,75,70,61,90,88,75,81

Arrange them in ascending order

52 61 70 75 75 76 81 88 89 90

We have 10 observations. 85the percentile represents the observation, below which 85% of the values lie.

location 85th percentile = 0.85*10= 8.5

Hence the location of 85th percentile is the 9th observation = 89

What score would represent the 10th percentile of the accuracy variable?

Accuracy: 77,66,82,

Arrange them in ascending order

66 77 82

We have 3observations. 10the percentile represents the observation, below which 10% of the values lie.

location 10th percentile = 0.1*3= 0.3

Hence the location of 10th percentile is the 1st observation = 66