Question

Boys Girls Total
Speech Therapist (ST) 30 30
Neuropsychologist (NP) 45 15
Psychiatrist(P) 30 10
Total

Botlhale and Mmabatho’s final project is to determine if specialist type and gender of chil-dren are independent of each other. Use 5% level of significance.





Question 18
Which of the following statements is incorrect?
(1) The null hypothesis is that specialist type and gender of children are independent of each other.
(2) The alternative hypothesis is that specialist type and gender of children are dependent.
(3) The expected frequency of boys consulting with Speech Therapists is 90.
(4) The observed frequency of boys consulting with Speech Therapists is 90.
(5) There are 3 degrees of freedom.

Answer 1

$$\def\arraystretch{1.5} \begin{array}{c:c:c:c} & Boys & Girls & Total \\ \hline Speech\ Therapist \ (ST) & 30 & 30 & 60\\ \hline Neuropsychologist\ (NP) & 45 & 15 & 60\\\hline Psychiatrist\ (P) & 30 & 10 & 40\\ \hdashline Total & 105 & 55 & 160 \end{array}$$

The following statements are wrong:

(4) The observed frequency of boys consulting with Speech Therapists is 90. 

(5) There are 3 degrees of freedom.