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
(x^2+4)^2 + 32 = 12x^2 + 48 .... a = x^2 + 4
<span>(x^2 + 4)^2 + 32 = 12(x^2 + 4) </span>
<span>a^2 + 32 = 12a </span>
<span>a^2 - 12a + 32 = 0 </span>
<span>(a - 8)(a - 4) = 0 </span>
<span>a = 8 and a = 4 </span>
<span>for a = 8 ... 8 = x^2 + 4 ... x^2 = 4 ... x = +/- 2 </span>
<span>for a = 4 ... 4 = x^2 + 4 ... x^2 = 0 ... x = 0 </span>
<span>x = -2, 0, +2 so your answer is going to be e
</span>
Answer:
C. 490.
Step-by-step explanation:
25% = 0.25.
If the number of emails that Ryan and Taylor each received is x emails then Sara received 2x + 0.25 * 2x = 2.5 emails.
So 2x + 2.5x = 882
x = 882/4.5
x = 196.
So Sara received 2.5 * 196
= 490 emails.
