1.) A researcher computes a Spearman rank-order correlation coefficient of –.26.
ID: 3180809 • Letter: 1
Question
1.) A researcher computes a Spearman rank-order correlation coefficient of –.26. The critical value needed to reject the null hypothesis is .38. The correct way to state the conclusion is:
a.) the population correlation coefficient is equal to zero.
b.) the population correlation coefficient is less than zero.
c.) the population correlation coefficient is not equal to zero.
d.) there is not sufficient reason to believe that the population correlation coefficient differs from zero.
2.) A researcher asks two judges to rank 20 patients according to their degree of psychopathology. The researcher would like the judges to be in substantial agreement. Which Spearman rank-order correlation coefficient for the judges’ ratings would the researcher most prefer?
a.) .63
b.) .50
c.) –.89
d.) 0
If two variables are highly positively correlated, which of the following must have approximately the same numerical value and the same sign?
a.) Neither
b.) both
c.) The paired z scores
d.) The paired raw scores
If we compute the correlation between scores on an intelligence test and grades in school, the correlation will be closest to zero for which of the following samples?
a.) Gifted children with IQs of at least 130
b.) Children from only the fourth through the eighth grades
c.) Children chosen randomly from the population
d.) Children with IQs between 90 and 130
It is more difficult to obtain a highly positive or a highly negative correlation between two variables when:
a.) the means of the raw scores of the two variables are very different.
b.) the means of the raw scores of the two variables are similar.
c.) the variability on both variables is extremely low.
d.) the variability on both variables is extremely high.
Explanation / Answer
1) since given correlation coffcient value and critical value ,but from that given data we cant calculate test statistic value so here we cant draw any conclusion so
d.) there is not sufficient reason to believe that the population correlation coefficient differs from zero.
2.since Researcher would like to judge in subtential agreement so if there is some relation in ordering by two docters then if the relation in +ve direction means ordering is approx in same direction then better for researcher so he need more +ve correlation cofficient hence
a.) .63
3.
if the 2 variables highly +vely correlated then its must be both variables have same sign but now its not mandetory that both have same numerical values but if we find Z score for both then we can get approx same numerical value
c.) The paired z scores
4.
if we want that correlation cofficient closest to zero between score of test and grades then it must needs the population for which test score and grades are not correlated so if we choose the sample randomly then we can get correlation approx zero because there all type of childrens that can avergae out corr cofficient to zero
c.) Children chosen randomly from the population
5.
we try to find high corr cofficient b/w two variales then we need covariance b/w both is high so if the variablity is low b/w both then we cant get high corr cofficient value
hence
c.) the variability on both variables is extremely low.
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