Question

Determine the type of correlation that exists in the given data set. Age (years) 23 45 39 74 63 52 59 28 35 11 26 49 IQ 76 82 113 111 109 115 101 127 92 123 128 99 A. According to this data, there is a positive correlation between age and IQ. B. According to this data, there is a negative correlation between age and IQ. C. According to this data, there is no correlation between age and IQ. D. There is not enough information in this data to determine what type of correlation exists between age and IQ.

Answer 1

Answer:

B -0.104

Step-by-step explanation:

Step 1: Write the formula for correlation

r =    total xy

√Total x² x Total y²

Step 2: Make a table to calculate all values

Table is attached in the picture below

Step 3 : Solve

Mean of X = Total X/ Total number of X

                  = 507/12

                  = 106.33

Mean of Y = Total Y/ Total number of Y

                  = 1276/ 12  

                  = 42.25

r =    total xy

√Total x² x Total y²

r = -352.05/ √3656.25 x 3122.66698

r = -0.104

-0.104 is negative

This negative correlation means there is an inverse correlation between variables.

Answer 2

Answer:

B. According to this data, there is a negative correlation between age and IQ.

Step-by-step explanation:

Correlation shows the strength of relation between two variables. The formula used to calculate correlation is:

$Correlation(r) = \frac{Cov(x, y)}{\sigma_{x}\sigma_{y}}= \frac{E(x-\mu_{x})(y-\mu_{y})}{\sigma_{x}\sigma_{y}}$

where, Cov(x,y) = Covariance of x and y

$\sigma_{x}$ = standard deviation of x

$\sigma_{y}$ = standard deviation of y

$\mu_{x}$ = mean of x

$\mu_{y}$ = mean of y

and, E denotes the Expectation.

The value of the correlation lies between -1 to +1.

If the value of correlation lies between -1 to 0 then it is known as a negative correlation.

and, If the value of correlation lies between 0 to 1 then it is known as a positive correlation.

Using the above formula of correlation we get Correlation (r) = -0.1225.

Thus, there is negative correlation between age and IQ.

We can also use a correlation calculator for getting the value of correlation.

Hence, option (B) is correct.