Given:
Sample proportion = 85% = 0.85.
Confidence level (CL) = 90%.
Confidence interval (CI)

We want the confidence interval to be 5% or 0.05. Therefore

Because this number is less than 1, a default sample size of 30 (for the normal distribution) is recommended.
Answer: 30
Answer:
first of all the formula
y = mx+c
where m is slope and c is y-intercept.
now substitute the values-
y = 2x - 5
(for the slope here is 2 and the part where the line intercepts y axis is -5
therefore
y = 2x-5
The reason why Fiona cannot make a valid prediction based on the mean of the population is that the variation of Fiona’s samples is too large.
<h3>Why can't Fiona use the means she recorded?</h3><h3 />
Mean is quite sensitive to outliers so it is best used when the variation between variables is not too much.
In Fiona's case, there variation is quite high with high variable of 95 compared to a low value of 45.
Find out more on effect of outliers at brainly.com/question/16815987.
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For half a year Kyle's phone bill would come up to be $170