Question:

In the article by Gadd and Phipps (2012), they refer to the challenges faced by psychological and, specifically, neuropsychological assessment. Their study focused on a preliminary standardisation of the Wisconsin Card Sorting Test (a non-verbal measure) for Setswana-speaking university students. The US normative sample is described as participants (N = 899) from both genders who were screened beforehand to exclude individuals with a history of neurological, learning, emotional and attention difficulties. The South African sample consisted of university students (N = 93) from both genders, between the ages of 18 and 29, who were screened in terms of hearing and visual impairments and any history of psychiatriceurological difficulties. The latter was done to prevent contamination of the results by these variables. The students were from the University of Limpopo, Medunsa Campus. Answer Questions 1 to 5.

Question 5

Gadd and Phipps (2012) found that the results of the South African sample on the Wisconsin Card Sorting Test did not resemble a normal distribution and could not be converted to a normal distribution. This implies that the ...

(1) mean performance of this sample cannot be calculated

(2) standard deviation will differ below and above the mean

(3) mean and standard deviation do not provide a predetermined distribution of performance

(4) results cannot be replicated

Would 1 be the correct answer?

1. A bivariate normal random vector (X1, X2)' is defined by X1 = M1 + 01 2 (1) X2 = 12 + 02 2 1 - PU2) where U1 and U2 are independent and standard normal random variables, of and 02 are positive numbers, #1 and /2 are real numbers, and -1 |Y = ) 9. Determine whether X and Y are independent.2) Bivariate data analysis The scatterplot below shows the relative deviation of the surface tempera- ture on earth measured in the Northern Hemisphere in dependence of the amount of carbon dioxide (CO2) in the atmosphere. The table displays 7 values that were taken out of the plotted data. CO2 in ppm rel.temp in C 321.38 -0.04 330.18 -0.14 310 win COyin ppm 341.45 0.07 Fid temperature daviation inc Hel. temperature deviationin 354.39 0.65 366.70 0.99 381.90 1.02 398.65 1.13 310 360 10 COjim ppm a) Make a scatterplot of the two data sets shown in the table in the empty coordinate system above. Is it reasonable to take this set for investigating the association of the measured data sets? b) Determine the mean values of the two sets. c) Determine the standard deviations of the two sets. d) Determine the covariance and the correlation coefficent. e) Determine the equation of the linear regression line. f) What are the meanings of intercept and slope? g) Make a quantitative assessment of the quality of your fit