as part of a cell phone plan the mitchell family can use 1,500 mintues each month without additional charges. there are 3 member
1 answer:
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Answer:
Interval [16.34 , 21.43]
Step-by-step explanation:
First step. <u>Calculate the mean</u>
Second step. <u>Calculate the standard deviation</u>
As the number of data is less than 30, we must use the t-table to find the interval of confidence.
We have 6 observations, our level of confidence DF is then 6-1=5 and we want our area A to be 80% (0.08).
We must then choose t = 1.476 (see attachment)
Now, we use the formula that gives us the end points of the required interval
where n is the number of observations.
The extremes of the interval are then, rounded to the nearest hundreth, 16.34 and 21.43
Answer:
The card was worth $160.
Step-by-step explanation:
It is given that:
Percent of gift card used = 42%
Cost of groceries = $67.20
Let,
x be the total amount on gift card.
42% of x = 67.20
0.42x = 67.20
Therefore,
The card was worth $160.