By assuming the standard deviation of population 2.2 the confidence interval is 8.67 toys,8.94 toys.
Given sample size of 1492 children,99% confidence interval , sample mean of 8.8, population standard deviation=2.2.
This type of problems can be solved through z test and in z test we have to first find the z score and then p value from normal distribution table.
First we have to find the value of α which can be calculated as under:
α=(1-0.99)/2=0.005
p=1-0.005=0.995
corresponding z value will be 2.575 for p=0.995 .
Margin of error=z*x/d
where x is mean and d is standard deviation.
M=2.575*2.2/
=0.14
So the lower value will be x-M
=8.8-0.14
=8.66
=8.67 ( after rounding)
The upper value will be x+M
=8.8+0.14
=8.94
Hence the confidence interval will be 8.67 toys and 8.94 toys.
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We know that the area of a square = side ²
Therefore, for a known area A, the side length is
side = √ (area)
= √ (175)
= 13.2288 (to 4 places of decimals).
0.37 I guess unless you push it up and it’s 3.7
7.5 km/h
Step-by-step explanation:
Let's assign the speed of Jerry in still air as <em>x </em> (in km/h)
Let's assign the speed of the wind as <em>y </em>(in km/h)
With the wind as Jerry’s back, he takes 10 minutes to get to the library. We can create the following equation. (<em>we are converting the minutes to hours by dividing by 60</em>);
2.5 / (x + y) = 10/60
10x + 10y = 150
x + y = 15
With the wind against Jerry, he takes 15 minutes from the library. We can create the following equation;
2.5 / (x-y) = 15/60
15x – 15y = 150
x – y = 10
We can now solve the simultaneous equation by subtraction;
x + y = 15
x – y = 10
2y = 5
y = 5/2 = 2.5
y = 2.5 km/h
x = 7.5 km/h
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Answer:
always, values, forms, an unlimited number of
Step-by-step explanation:
brainliest?
