Semester 1:
let the number of students in the art class be 2a, and the number of the students in the gym class be 7a. (check: the ratio is 2a:7a = 2:7)
so the total number of students is 9a.
semester 2:
the 9a students are go to the art class and gym class at a a ratio of 5: 4,
so 5a students go to the art class, and 4a students go to the gym class.
<span>75 students are in art class in second semester means that 5a=75,
so a=75/5=15.
In the 1st semester the number of students was:
art class: 2a=2*15=30
gym class: 7a=7*15=105</span>
Answer:
the top one that's orange
Answer:
B = 15
Step-by-step explanation:
<u>Combine multiplied terms into a single fraction</u>
6 + 2b/5 = 12
<u>Subtract 6 from both sides</u>
6 + 2b/5 <em>(-6)</em> = 12 <em>(-6) </em>= 2b/5 = 6
<u>Multiply all terms by the same value to eliminate fraction denominators</u>
2b/5 <em>( x 5) </em>= 6<em> (x 5)</em>
<em />
<u>Simplify</u>
2b = 30
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:
Step-by-step explanation:
1. not equivalent
2. not equivalent
3. fully simplified
4.not fully simplified
5. not fully simplified
6. not fully simplified