Answer: 5/24
Step-by-step explanation:
The problem is 7/12-3/8. I got a common denominator of 24, then multipled 8 and 3 by 3, and 7 and 12 by 2. The problem is now 14/25-9/24, which equals 5/24
Answer:
The value of the test statistic is z = -0.877.
Step-by-step explanation:
Testing the difference in mean time spent on housework between husbands and wives.
At the null hypothesis, we test if there is no difference, that is, the subtraction of the means is 0:

At the alternate hypothesis, we test if there is a difference, that is, the subtraction of the means is different from 0.

The test statistic is:

In which X is the sample mean,
is the value tested at the null hypothesis, and s is the standard error.
0 is tested at the null hypothesis:
This means that 
For the wives the mean was 7 hours/week and for the husbands the mean was 4.5 hours/week. The standard deviation of the differences in time spent on house work was 2.85.
This means that 
What is the value of the test statistic for testing the difference in mean time spent on housework between husbands and wives?



The value of the test statistic is z = -0.877.
Answer:
56.25 pound of the coffee that costs $5 per pound is needed
18.75 pound of the coffee that costs $9 per pound is needed
Step-by-step explanation:
Let the number of pounds be x and y respectively
The total pounds is 75;
So;
x + y. = 75 •••••••(i)
Total cost of first type
9 * x = $9x
Total cost of second type;
5 * y= $5y
75 pound at $6 per pound; total cost of this is;
6 * 75 = $450
Thus;
9x + 5y = 450 ••••••••(ii)
From i, x = 75-y
Put this into ii
9(75-y) + 5y = 450
675 -9y + 5y = 450
4y = 675-450
4y = 225
y = 225/4
y = 56.25
x = 75 - y from i
x = 75-56.25
x = $18.75