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Rory suspects that teachers in his school district have less than 5 yearſ of experience on average. He
decided to test Ha :u= 5 versus H : u < 5 using a sample of 25 teachers. His sample mean was 4
years and his sample standard deviation was 2 years.

Respuesta :

Answer:

Teachers in his school district have less than 5 yearſ of experience on average is true.

Step-by-step explanation:

Sample mean = [tex]\bar{x}=4[/tex]

Sample standard deviation = s = 2

We are supposed to to test Ha :u= 5 versus H : u < 5 using a sample of 25 teachers

[tex]H_a:\mu=5\\H_0:\mu < 5[/tex]

n = 25

Since n<30 and population standard deviation is unknown

So, we will use t test

Formula : [tex]t=\frac{x-\mu}{\frac{s}{\sqrt{n}}}[/tex]

[tex]t=\frac{4-5}{\frac{2}{\sqrt{25}}}[/tex]

t=-2.5

[tex]\alpha = 0.05[/tex]

Degree of freedom = n-1 = 25-1 = 24

Refer the t table

[tex]t_{df,\frac{\alpha}{2}}=t_{24,\frac{0.05}{2}}=2.064[/tex]

t critical > t calculated

So, We are failed to reject null hypothesis

So,  teachers in his school district have less than 5 yearſ of experience on average is true.

The statement is true that the teacher in Rory school have less than five years of experience on average.

Statistics

According to the question,

Sample mean, [tex]\bar x[/tex] = 4

Standard deviation, s = 2

Sample number of teachers, n = 25

Test:

[tex]H_a[/tex] : μ = 5

[tex]H_0[/tex] : μ < 5

We know the formula,

→ t = [tex]\frac{x- \mu}{\frac{s}{\sqrt{n} } }[/tex]

By substituting the values,

    = [tex]\frac{4- 5}{\frac{2}{\sqrt{25} } }[/tex]

    = -2.5

Now, the degree of freedom be:

= n - 1

= 25 - 1

= 24

By using t-table,

[tex]t_{df,\frac{\alpha}{2} }[/tex] = [tex]t_{24,\frac{0.05}{2} }[/tex]

       = 2.064

We can say that [tex]t_{critical}[/tex] > [tex]t_{calculated}[/tex]

Thus the response above is correct.

Find out more information about standard deviation here:

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