A recent study discovered the correlation between the age at which an infant first speaks and the child’s score on an IQ test given upon entering elementary school is $-0.68$. A scatterplot of the data shows a linear form. Which of the following statements about this finding is correct?

(a) Infants who speak at very early ages will have higher IQ scores by the beginning of elementary school than those who begin to speak later.

(b) $68\%$of the variation in IQ test scores is explained by the least-squares regression of age at first spoken word and IQ score.

(c) Encouraging infants to speak before they are ready can have a detrimental effect later in life, as evidenced by their lower IQ scores.

(d) There is a moderately strong, negative linear relationship between age at first spoken word and later IQ test scores for the individuals in this study.

Step by step solution

01

Given Information

It has been investigated in the study that the association between the score ofIQ test by the child which is given at the time of taking admission in elementary school and the age at which child starts speaking is $-0.68$.

02

Explanation

It is a measure of the correlation between two numerical or quantitative variables.

A correlation value of $-1$to $1$is computed to describe the relationship between the two variables.

The correlation coefficient is$-0.68$in this case.

The graph shows the two variables have a moderately negative clear linear relationship.

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