The Jefferson Valley Bank once had a separate customer waiting line at each teller window, but it now has a single waiting line that feeds the teller windows as vacancies occur. The standard deviation of customer waiting times with the old multiple-line configuration was 1.8 min. Listed below is a simple random sample of waiting times (minutes) with the single waiting line. Use a 0.05 significance level to test the claim that with a single waiting line, the waiting times have a standard deviation less than 1.8 min. What improvement occurred when banks changed from multiple waiting lines to a single waiting line?

Respuesta :

Answer:

There will be sufficient evidence to conclude. A further explanation is provided below.

Step-by-step explanation:

The given values are:

[tex]\sigma=1.8[/tex]

[tex]\alpha=0.05[/tex]

[tex]n=10[/tex]

As we know,

[tex]\bar{x}=\frac{\Sigma x_i}{n}[/tex]

  [tex]=\frac{71.5}{10}[/tex]

  [tex]=7.15[/tex]

The standard deviation will be:

⇒  [tex]s=\sqrt{\frac{1}{n-1} \Sigma(x_i- \bar{x})^2 }[/tex]

On substituting the values, we get

⇒     [tex]=\sqrt{\frac{1}{10-1} [(6.5-7.15)^2+...(7.7-7.15)^2]}[/tex]

⇒     [tex]=\sqrt{\frac{1}{9} [(6.5-7.15)^2+...(7.7-7.15)^2]}[/tex]

⇒     [tex]=0.477[/tex]

According to the question,

Hypotheses:

[tex]H_o: \sigma=1.8[/tex]

[tex]H_a: \sigma<1.8[/tex]

The test statistic will be:

⇒ [tex]X^2=\frac{(n-1)s^2}{\sigma^2}[/tex]

⇒       [tex]=\frac{(10-1)\times 0.477^2}{1.8^2}[/tex]

⇒       [tex]=\frac{2.0477}{3.24}[/tex]

⇒       [tex]=0.632[/tex]

Thus the above is the correct response.