Answer:
b
Step-by-step explanation:
If you multiple each side by 3 then they will equal the numbers that b has
Answer:
30/100=30%. 98-30%=68%, which will be your new grade. That is usually a D
Step-by-step explanation:
I believe it's 2160. Sounds right to me
Answer:
C) H0:μd=0 and Ha:μd≠
0
Null hypothesis:
Alternative hypothesis: 
Step-by-step explanation:
A paired t-test is used to compare two population means where you have two samples in which observations in one sample can be paired with observations in the other sample. For example if we have Before-and-after observations (This problem) we can use it.
Let put some notation
x=value for the first shop , y = value for the second shop
The system of hypothesis for this case are:
Null hypothesis:
Alternative hypothesis: 
Or equivalently :
Null hypothesis:
Alternative hypothesis: 
Since we define the difference
and we obtain this:
The second step is calculate the mean difference
The third step would be calculate the standard deviation for the differences, and we got:
The 4 step is calculate the statistic given by :
The next step is calculate the degrees of freedom given by:
Now we can calculate the p value, since we have a two tailed test the p value is given by:
C) H0:μd=0 and Ha:μd≠
0
Answer: a) is right
Step-by-step explanation: Mode is 26 because there are more numbers 26 than others. Median is average of two numbers in middle because there are even amount of numbers, also 0.5·(21+23)= 22. Average is 22.4