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The director of a state agency believes that the average starting salary for clerical employees in the state is less than $30,000 per year. To test her hypothesis, she has collected a random sample of 100 starting clerical salaries from across the state and found that the sample mean is $29,750. a) Develop the appropriate null and alternative hypotheses. b) Assuming the standard deviation is known to be $2,500 and the significance level for the test is to be 0.05, what is the t-statistic

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okpalawalter8

Answer:

The test statistics is   [tex]z = -1[/tex]  

Step-by-step explanation:

From the question we are told that

   The sample size is  n  =  100

  The null hypothesis  is  [tex]H_o : \mu = \$30000[/tex]

   The alternative hypothesis is  [tex]H_a : \mu < \$ 30000[/tex]

   The sample mean is  [tex]\= x = \$29,750[/tex]

    The standard deviation is  [tex]\sigma = \$2,500[/tex]

    The level of significance is  [tex]\alpha =0.05[/tex]

Generally the test statistics is mathematically represented as

        [tex]z = \frac{\= x - \mu }{ \frac{ \sigma}{ \sqrt{n} } }[/tex]

=>      [tex]z = \frac{29750 - 30000 }{ \frac{ 2500}{ \sqrt{100} } }[/tex]

=>      [tex]z = -1[/tex]    

From the desired test, we have that:

a)

  • The null hypothesis is: [tex]H_0: \mu \geq 30000[/tex]
  • The alternative hypothesis is: [tex]H_1: \mu < 30000[/tex]

b) The t-statistic is t = -1.

Item a:

At the null hypothesis, we test if the average starting salary for clerical employees in the state is not less than $30,000, that is:

[tex]H_0: \mu \geq 30000[/tex]

At the alternative hypothesis, it is tested if the salary is less than $30,000, that is:

[tex]H_1: \mu < 30000[/tex]

Item b:

We have the standard deviation for the sample, thus, the t-distribution is used. The test statistic is given by:

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

The parameters are:

  • [tex]\overline{x}[/tex] is the sample mean.
  • [tex]\mu[/tex] is the value tested at the null hypothesis.
  • s is the standard deviation of the sample.
  • n is the sample size.

For this problem, the values of the parameters are: [tex]\overline{x} = 29750, \mu = 30000, s = 2500, n = 100[/tex]

Hence, the t-statistic is:

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

[tex]t = \frac{29750 - 30000}{\frac{2500}{\sqrt{100}}}[/tex]

[tex]t = -1[/tex]

The t-statistic is t = -1.

A similar problem is given at https://brainly.com/question/13873630