Answer:
<h3>73220±566.72</h3>
Step-by-step explanation:
The formula for calculating the confidence interval is expressed as;
CI = xbar ± z*s/√n
xbar is the sample mean = $73,220
z is the z score at 99% CI = 2.576
s is the standard deviation = $4400
n is the sample size = 400
Substitute the given values into the formula;
CI = 73,220 ± 2.576*4400/√400
CI = 73,220 ± 2.576*4400/20
CI = 73,220± (2.576*220)
CI = 73220±566.72
Hence a 99% confidence interval for μ is 73220±566.72
Answer:
1899
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 3234
Standard deviation = 871
Percentage of newborns who weighed between 1492 grams and 4976 grams:
1492 = 3234 - 2*871
So 1492 is two standard deviations below the mean.
4976 = 3234 + 2*871
So 4976 is two standard deviations above the mean.
By the Empirical Rule, 95% of newborns weighed between 1492 grams and 4976 grams.
Out of 1999:
0.95*1999 = 1899
So the answer is 1899
Answer:
21 pencils
Step-by-step explanation:
b 21 pencils
Subtract 3/4x from both sides
1/3x-4-3/4x= 3/4x+1-3/4x
-5/12x-4=1
Add 4 to both sides
-5/12x-4+4=1+4
-5/12x=5
Multiply both sides by 12/(-5)
(12/-5)*(-5/12x)= (12/-5)*(5)
x= 12
I hope that's help.
