Answer:
2
Step-by-step explanation:
X-20 = Y+20........ X-Y = 20+20........
X-Y = 40
AND
2Y-44=X+22............. Y-X= 44+22
Y-X=66
NOW, LET'S FIND X AND Y FROM THESE TWO EQUATIONS....
X-Y =40
Y-X= 66
IF WE COLLECT ....... 2Y = 106 AND Y = 53
THEN, USE Y IN ANY EQUATIONS FOR FINDING X
X-53 = 40 ..... X= 53+40 .......... X= 93
X= 93
Y=53
Answer:
Step-by-step explanation:
The mean SAT score is
, we are going to call it \mu since it's the "true" mean
The standard deviation (we are going to call it
) is

Next they draw a random sample of n=70 students, and they got a mean score (denoted by
) of 
The test then boils down to the question if the score of 613 obtained by the students in the sample is statistically bigger that the "true" mean of 600.
- So the Null Hypothesis 
- The alternative would be then the opposite 
The test statistic for this type of test takes the form

and this test statistic follows a normal distribution. This last part is quite important because it will tell us where to look for the critical value. The problem ask for a 0.05 significance level. Looking at the normal distribution table, the critical value that leaves .05% in the upper tail is 1.645.
With this we can then replace the values in the test statistic and compare it to the critical value of 1.645.

<h3>since 2.266>1.645 we can reject the null hypothesis.</h3>