Calculate the sum of 12.7, 24.8, 4.1
1 answer:
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Answer:
The test statistic is z = -2.11.
Step-by-step explanation:
Before finding the test statistic, we need to understand the central limit theorem and subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
Group 1: Sample of 35, mean of 1276, standard deviation of 347.
This means that:
Group 2: Sample of 35, mean of 1439, standard deviation of 298.
This means that:
Test if there is a difference in productivity level.
At the null hypothesis, we test that there is no difference, that is, the subtraction is 0. So
At the alternate hypothesis, we test that there is difference, that is, the subtraction is different of 0. So
The test statistic is:
In which X is the sample mean, is the value tested at the null hypothesis and s is the standard error.
0 is tested at the null hypothesis:
This means that
From the two samples:
Test statistic:
The test statistic is z = -2.11.
Answer:
Step-by-step explanation:
we know that
To find out the probability of hitting a ball into the circular hole, divide the area of the hole by the area of the playing area
Let
x ----> the area of the hole
y ----> the area of the playing game
so
we have
<em>Find the area of the hole</em>
The area of the circle (hole) is equal to
we have
----> the radius is half the diameter
assume
substitute
<em>Find the probability</em>
we have
substitute
Convert to percentage
Round to the nearest tenth