Answer:
The standard deviation has changed for the worse
Step-by-step explanation:
We need to compare the sample standard deviation of 52.3 to the known population standard deviation of 43.7. The test we will use will use Chi-Square distribution...
The hypothesis for this test are...
H0: σ = 43.7
Ha: σ ≠ 43.7
This is a 2 tailed test.
We have n = 81
s = 52.3
s² = 52.3² = 2735.29
σ = 43.7
σ² = 1909.69
The degrees of freedom are: n - 1, in this case, 80
Our significance level is 95%, so our critical values are
Χ² < 57.153 and Χ² > 106.629
The test static is found with the formula:
Χ² = [(n - 1)s²]/σ²
Plug in what we have and find the test stastic....
Χ² = [80(2735.29)]/1909.69
Χ² = 114.586
114.586 > 106.629, we reject the null hypothesis. There is evidence that shows that the standard deviation has changed. The evidence suggests that it has increased, which would make the new method worse than the old method.
(might not be correct and I don't know what it's asking/its confusing)
Answer:
Karen's music library has 11 playlists
Clarann's music library has 29 playlists
Step-by-step explanation:
29+11=40
this is what I did:
I know that Clarann has at least 18,
Karen: 0 1 2 3 4 5 6 7 8 9 10 11
clarann:18 19 20 21 22 23 24 25 26 27 28 29
total: 18 20 22 24 26 28 30 32 34 36 38 40
Answer:answer choice a : rtation 90 degres around the origon
Step-by-step explanation:
X*6+1=31
5*6=30
30+1=31
x*7-4=31
5*7=35
35-4=31
Hope this helps! If you have any questions, just ask me!
She must win the next 8 consecutive games to get 80% and after that loose the next 12 games to get to 50%.
<h3>How to find the probability of winning?</h3>
She has won 8 out of 12 days. Thus, percentage of winning is;
P(winning) = 8/12 * 100%
P(Winning) = 75%
To arrive at 80% winning, it means that the number of extra consecutive games she must win is;
(8 + x)/(12 + x) = 80/100
10(8 + x) = 8(12 + x)
80 + 10x = 96 + 8x
2x = 16
x = 8
Thus, she must win the next 8 consecutive games to get 80%.
For her to get to 50% after that, it means that;
(16 - x)/(20 - x) = 50/100
(16 - x)/(20 - x) = 1/2
2(16 - x) = 20 - x
32 - 2x = 20 - x
x = 12
Read more about Probability of winning at; brainly.com/question/24756209
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