Please help with this

dimulka [17.4K]

Answer:

Step-by-step explanation:

3 0

4 years ago

A maintenance manager must test a new repair method that should increase the expected time between repairs. For each machine use

Murljashka [212]

Answer:

a) The value t=1.73 < 1.833 fall in the acceptance region, so the effect is not significant. The null hypothesis can not be rejected.

The claim that the new method is better doesn't have enough statistical evidence.

b) P-value=0.06

c) 95% CI

$-25 \leq\mu_n-\mu_c\leq 189$

Step-by-step explanation:

A) We have to test the hypothesis about the difference of the means.

The claim is that the new method gives larger times between repairs.

1) State the null and alternative hypothesis

$H_0: \mu_n\leq\mu_c\\\\H_a: \mu_n>\mu_c$

The significance level is 0.05.

2) The sample mean and standard deviation of the current method is

$M_c=254\\\\ s_c=113$

The sample mean and standard deviation of the new method is

$M_n=336\\\\ s_n=99$

The difference of means is

$M_d=M_n-M_c=336-254=82$

The standard deviation of the difference of means can be estimated as:

$s_d=\sqrt{\frac{s_n^2+s_c^2}{n} }=\sqrt{\frac{99^2+113^2}{10} }=\sqrt{2246}=47.4$

3) Then, we can calculate the t-statistic as:

$t=\frac{M_d-(\mu_n- \mu_c)}{s_d} =\frac{82-0}{47.4}=1.73$

4) For 9 degrees of freedom and a significance level of 0.05, the critical value for t is t=1.833.

5) The value t=1.73 < 1.833 fall in the acceptance region, so the effect is not significant. The null hypothesis can not be rejected.

The claim that the new method is better doesn't have enough statistical evidence.

B) For a df=10-1=9 and t=1.73, the P-value is

$P(t_9>1.73)=0.06$

C) In this case, for 9 degrees of freedom and 95% CI, the critical value of t is t=2.262.

The CI can be written as:

$M_d-t*s_d\leq\mu_n-\mu_c\leqM_d+t*s_d\\\\82-2.262*47.4\leq\mu_n-\mu_c\leq 82+2.262*47.4\\\\82-107\leq\mu_n-\mu_c\leq 82+107\\\\-25 \leq\mu_n-\mu_c\leq 189$

7 0

3 years ago

5 1/4 *8/9 *8/21 now i need it pls help

lyudmila [28]

Answer:

Step-by-step explanation:

5 1/4 is converted to 21/4. Then you multiple 8/9 and 8/21 which is: 21/4*8/9*8/21=16/9 and is 17.777777778

3 0

4 years ago

11154 ÷ 52. Express the remainder as a fraction in the lowest terms

Andrew [12]

11154/52= 214 1/2 is the answer to this question

5 0

3 years ago

Which is the ordered pair for the point on the x-axis that is on the line parallel to the given line and through the given point

N76 [4]

Answer:

Option (1). (6, 0)

Step-by-step explanation:

The given question is incomplete; here is the complete question.

Which is the ordered pair for the point on the x-axis that is on the line parallel to the given line and through the given point (–6, 10)?

(6, 0)

(0, 6)

(−5, 0)

(0, −5)

Line in orange color is passing through two points (-8, 6) and (4, -4)

Slope of this line = $\frac{\triangle y}{\triangle x}$

= $\frac{6+4}{-8-4}$

= $-\frac{10}{12}$

= $-\frac{5}{6}$

Other line parallel to this line will have the same slope 'm' = $-\frac{5}{6}$

Parallel line passes through a point (-6, 10).

Let the other point through which the parallel line passes is (a, b)

Now, $-\frac{5}{6}$ = $\frac{10-b}{-6-a}$

-5(-a - 6) = 6(10 - b)

5a + 30 = 60 - 6b

5a = -6b + 60 - 30

5a = -6b + 30

a = $-\frac{6}{5}b+6$

By satisfying with all the options we find only (6, 0) satisfy this equation.

6 = $-\frac{6}{5}(0)+6$

6 = 6

Therefore, (6, 0) is the other point lying on the parallel line.

Option (1) will be the answer.

8 0

3 years ago

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