Here’s the answer…Hope this helps?
Answer:
1.8%
Step-by-step explanation:
2.85-2.80=$0.05
$0.05 x 100 = 5
5/2.80=1.78
1.8
Answer $220 dollars
Margo spent 220 dollars at the concert.
Answer:
Step-by-step explanation:
Confidence interval is one which has centre as mean. The width of the interval would be 2 times margin of error.
Margin of error = Critical value * Std error/sq rt of sample
Hence if margin of error is lower for same n, then it means lower confidence level. Option a is right
Similarly, if bigger the sample size, lower is margin of error . Hence option b is right
c) False. Smaller samples make margin of error big and hence confidence intervals bigger.
d) If n becomes 9n, then margin of error becomes 1/3 Hence option d is right.
We are given the following variables:
μ = the sample mean = 152 pounds
σ = the standard deviation = 26 pounds
x = the sample value we want to test = 180 pounds
n = the sample size = unknown
MOE = margin of error = 4% = 0.04
Confidence level = 96%
The first thing we can do is to find for the value of z
using the formula:
z = (x – μ) / σ
z = (180 – 152) / 26
z = 1.0769 = 1.08
Since we are looking for the people who weigh more than
180 pounds, therefore this is a right tailed z test. The p value is:
p = 0.1401
Then we can use the formula below to solve for n:
n = z^2 * p * (1 – p) / (MOE)^2
n = 1.08^2 * 0.1401 * (1 – 0.1401) / (0.04)^2
n = 87.82 = 88
Therefore around 88 people must be surveyed.