Answer:
d. t distribution with df = 80
Step-by-step explanation:
Assuming this problem:
Consider independent simple random samples that are taken to test the difference between the means of two populations. The variances of the populations are unknown, but are assumed to be equal. The sample sizes of each population are n1 = 37 and n2 = 45. The appropriate distribution to use is the:
a. t distribution with df = 82.
b. t distribution with df = 81.
c. t distribution with df = 41.
d. t distribution with df = 80
Solution to the problem
When we have two independent samples from two normal distributions with equal variances we are assuming that
And the statistic is given by this formula:
Where t follows a t distribution with 
degrees of freedom and the pooled variance 
is given by this formula:
This last one is an unbiased estimator of the common variance 
So on this case the degrees of freedom are given by:
And the best answer is:
d. t distribution with df = 80
Answer:
153.9 ft²
Step-by-step explanation:
Given that:
Radius of circular lawn = 7 feets
To obtain the maximum number of square feet of lawn Nichole can expect the sprinkler to cover ; find the area of the lawn
Area of a circle, A = πr²
A = π * 7 * 7
A = 153.93804
A = 153.9 ft²
Answer:
Just divide the 224 out of the total 560
40%
Step-by-step explanation:
There are 33/20 or 1.65 pounds left.
Given:
4 3/4 pounds of clay
1 1/10 pounds of clay for a cup
2 pounds of clay for a jar
Convert the mixed fraction into fractions.
4 3/4 = (4*4+3)/4 = 19/4
1 1/10 = (1*10+1)/10 = 11/10
2 = 2/1
19/4 - 11/10 = (19/4 *5/5) - (11/10 * 2/2) = 95/20 - 22/20
= (95-22)/20 = 73/20 or 3.65 pounds after making a cup
73/20 - 2/1 = 73/20 - (2/1 * 20/20) = 73/20 - 40/20 = 73 - 40 / 20 = 33/20 OR 1.65 pounds left after making a jar.
We can also convert the fractions into decimal numbers.
19/4 = 4.75
11/10 = 1.10
2/1 = 2.00
4.75 - 1.1 - 2 = 1.65 pounds left.
