Answer:
Step-by-step explanation:
Given that a professor sets a standard examination at the end of each semester for all sections of a course. The variance of the scores on this test is typically very close to 300.

(Two tailed test for variance )
Sample variance =480
We can use chi square test for testing of hypothesis
Test statistic = 
p value = 0.0100
Since p <0.05 our significance level, we reject H0.
The sample variance cannot be claimed as equal to 300.
Answer:
,
,
,
....e.t.c are all equivalent fractions
Step-by-step explanation:
For the answer you need to know bout equivalent fractions
TO find equivalent fractions you have to multiply the numerator and denominator by the same amount
E.x.
Therefore
is an equivalent fraction
6= 4(z+9)/y+2
6y +12 =4(z+9)
6y=4(z+9) -12
y=(4(z+9)-12)/6
y=2z+18-6/3
y=2z+12 /3