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Juliette [100K]
4 years ago
10

Using traditional methods, it takes 108 hours to receive a basic driving license. A new license training method using Computer A

ided Instruction (CAI) has been proposed. A researcher used the technique with 270 students and observed that they had a mean of 107 hours. Assume the variance is known to be 49. A level of significance of 0.1 will be used to determine if the technique performs differently than the traditional method. Find the value of the test statistic. Round your answer to 2 decimal places. Enter the value of the test statistic.
Mathematics
1 answer:
Rainbow [258]4 years ago
4 0

Answer: z= -2.35

Step-by-step explanation:

When the population variation is know, then we calculate the z-statistic.

Formula to calculate the z-test statistic is given by :-

z=\dfrac{\overline{x}-\mu}{\dfrac{s}{\sqrt{n}}}

where , n= sample size

\overline{x} = sample mean

\mu = Population mean

\sigma =Population standard deviation.

As per given we have,

n= 270

\mu= 108

\overline{x}=107

\sigma^2=49\\\\\Rightarrow \sigma=\sqrt{49}=7

Then, z-statistic  will be

z=\dfrac{107-108}{\dfrac{7}{\sqrt{270}}}    (Substitute all the values )

\Rightarrow\ z=\dfrac{-1}{\dfrac{7}{16.4316767252}}  

\Rightarrow\ z=\dfrac{-1}{0.426006433614}  

\Rightarrow\ z=-2.34738238931\approx-2.35  

Hence, the value of the test statistic= z= -2.35

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