Answer:
well you got to tell us what we're helping you with!
Step-by-step explanation:
Answer:
17
Step-by-step explanation:
I believe that is the answer
3? i think so i don’t know if it’s right
Answer:
x=8
y = 3
Step-by-step explanation:
x-y=5 and y=11-x
Substitute the second equation into the first
x - (11-x) = 5
Distribute the minus sign
x -11+x = 5
Combine like terms
2x-11 =5
Add 11 to each side
2x-11+11=5+11
2x=16
Divide by 2
2x/2 = 16/2
x=8
Now find y
y=11-x
y=11-8
y=3
We have:
n = 161
xbar = 32.8hg
s = 7.2hg
cl = 90% = 0.90
Since we have only the sample standard deviation s, we need to use the t-distribution.
The degrees of freedom DF = 161 - 1 = 160
α = (1 - 0.90)/2 = 0.05
If you look at these values in a t-distribution table you find t = 1.65
Now we can build the confidence interval:
xbar +/- (t · s /√n) = 32.8 +/- (1.65 · 7.2 / √161)
Therefore:
31.86 < μ < 33.74
In order to understand if these values are different from the ones you are given, let's calculate the confidence interval for the latest:
n = 12
xbar = 33.1hg
s = 2.7hg
31.7 < μ < 34.5
Calculate the error: (34.5 - 33.1) = (33.1 - 31.7) = 1.4
We know t · s /√n = 1.4
and we can solve for t:
t = 1.4 · √n / s = 1.4 · √12 / 2.7 = 1.7962
Looking at a t-distribution table, we find α = 0.05
which brings to a confidence level of 90%, which is the same for the previous part.
Since the sample size is big enough, we can use the normal distribution and the z-score:
Looking at a normal distribution table, we find z-score = 1.645, which is very similar to the t-value found previously. We don't know the population standard deviation, but for such a big sample the sample standard deviation is a good estimate, therefore:
<span>xbar +/- (z* · s /√n) = 32.8 +/- (1.645 · 7.2 / √161)
</span><span>31.8 < μ < 33.7</span>