The confidence interval formula is computed by:
Xbar ± Z s/ sqrt (n)
Where:
Xbar is the mean
Z is the z value
S is the standard deviation
N is the number of samples
So our given are:
90% confidence interval with a z value of 1.645
Sample size 40, 45
Mean 180, 179
Standard deviation 2, 4
So plugging that information in the data will give us a
confidence interval:
For 1:
Xbar ± Z s/ sqrt (n)
= 180 ± 1.645 (2 / sqrt (40))
= 180 ± 1.645 (0.316227766)
= 180 ± 0.520194675
= 179.48, 180.52
For 2:
Xbar ± Z s/ sqrt (n)
= 179 ± 1.645 (4 / sqrt (45))
<span>= 179 ± 1.645 (0.596284794)</span>
therefore, the answer is letter b
The markdown rate is 66.7%.
<h3>Markdown rate</h3>
Using this formula
Markdown rate= Change in price/original price×100
Let plug in the formula
Markdown rate=$1.50-$0.50/$1.50
Markdown rate=$1.00/$1.50×100
Markdown rate=66.66%
Markdown rate=66.7% (Approximately)
Inconclusion the markdown rate is 66.7%.
Learn more about markdown rate here:brainly.com/question/1153322
Im not in this math section yet but i think that you can look it up as a worksheet and find the answer on google.
