Answer:
(A) The data set of the sample of students who has taken a calculus test is right skewed.
(B) The average of female students in the class is 66.
Step-by-step explanation:
(A)
For a left skewed distribution the Mean < Median < Mode.
For a right skewed distribution the Mean > Median > Mode.
For a symmetric distribution the Mean = Median = Mode.
Given: Mean = 78.2, Median = 67 and Mode = 67
In this case the mean of the data is more than the median and mode.
[tex]Mean = 78.2>Median = Mode = 67[/tex]
Thus, the data set of the sample of students who has taken a calculus test is right skewed.
(B)
Total number of student ([tex]n[/tex]) = 35
Combined average ([tex]\mu_{c}[/tex]) = 70
Number of male student ([tex]n_{M}[/tex]) = 20
Average of male students ([tex]\mu_{M}[/tex]) = 73
Number of female student ([tex]n_{F}[/tex]) = 15
Average of female students = [tex]\mu_{F}[/tex]
The formula to compute the combined average is:
[tex]\mu_{c}=\frac{n_{M}\mu_{M}+n_{F}\mu_{F}}{n_{M}+n_{F}}[/tex]
Compute the value of [tex]\mu_{F}[/tex] as follows:
[tex]\mu_{c}=\frac{n_{M}\mu_{M}+n_{F}\mu_{F}}{n_{M}+n_{F}}\\70=\frac{(20\times73)+(15\times\mu_{F})}{20+15}\\ 70\times35=1460+(15\times\mu_{F})\\\mu_{F}=\frac{2450-1460}{15} \\=66[/tex]
Thus, the average of female students in the class is 66.