1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
melamori03 [73]
3 years ago
8

The mean time required to repair breakdowns of a certain copying machine is 93 minutes. The company which manufactures the machi

nes claims that breakdowns of its new, improved model are easier to fix. To test this claim, sample of 73 breakdowns of the new model were observed, resulting in a mean repair time of 88.8 minutes and a standard deviation of 26.6 minutes. Use significance level α = 0.05. State clearly what are your null and alternative hypothesis, show your work, and state your conclusion.
Mathematics
1 answer:
Sonja [21]3 years ago
5 0

Answer:

t=\frac{88.8-93}{\frac{26.6}{\sqrt{73}}}=-1.349    

p_v =P(t_{(72)}  

If we compare the p value and the significance level given \alpha=0.05 we see that p_v>\alpha so we can conclude that we have enough evidence to fail reject the null hypothesis, and we can't concluce that the true mean is less than 93 min at 5% of signficance.  

Step-by-step explanation:

Data given and notation  

\bar X=88.8 represent the sample mean

s=26.6 represent the sample standard deviation for the sample  

n=73 sample size  

\mu_o =93 represent the value that we want to test

\alpha=0.05 represent the significance level for the hypothesis test.  

t would represent the statistic (variable of interest)  

p_v represent the p value for the test (variable of interest)  

State the null and alternative hypotheses.  

We need to conduct a hypothesis in order to check if the true mean i lower than 93 min, the system of hypothesis would be:  

Null hypothesis:\mu \geq 93  

Alternative hypothesis:\mu < 93  

If we analyze the size for the sample is > 30 but we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:  

t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}  (1)  

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".  

Calculate the statistic

We can replace in formula (1) the info given like this:  

t=\frac{88.8-93}{\frac{26.6}{\sqrt{73}}}=-1.349    

P-value

The first step is calculate the degrees of freedom, on this case:  

df=n-1=73-1=72  

Since is a one side test the p value would be:  

p_v =P(t_{(72)}  

Conclusion  

If we compare the p value and the significance level given \alpha=0.05 we see that p_v>\alpha so we can conclude that we have enough evidence to fail reject the null hypothesis, and we can't concluce that the true mean is less than 93 min at 5% of signficance.  

You might be interested in
Jim decided to go for a drive in his car. He started out at 0 miles per hour (mph). He then
Ghella [55]

20+35-11 - 7 =37 !

i calculated it ;)

6 0
3 years ago
Read 2 more answers
Some one please help me with this question
pychu [463]
The answer is C because you do PEMDAS and then add the 5 from the other side
5 0
3 years ago
The ratio of pounds of vegetables to pounds of protein on the dinner plate is 5 to 2. IF
leva [86]

Answer:

10 lbs

Step-by-step explanation:

25 is to 5    as   x is to 2

25/5 = x/2

2 * 25/5 = x = 10 lbs

8 0
2 years ago
Find the perimeter of the<br> triangle.<br> 16% + 16) cm<br> (9%-11) cm
maxonik [38]

Answer:

Step-by-step explanation:

Three equal sides, so lets find one by solving for x

6x + 16 = 9x-11

      -3x = -27

         x = 9

6(9) + 16 = 70

 9(9) - 11 = 70

70(3) = 210 cm

8 0
3 years ago
To convert gallons to quarts, multiply by the conversion rate of 4qt /1gal <br><br> true or false
erma4kov [3.2K]
The answer is 100% TRUE
5 0
3 years ago
Other questions:
  • 5(- 3x - 2) - (x - 3) = -4(4x + 5) + 13 Solve
    11·2 answers
  • What is the equivalent for a 6.5 x * x + 5 .5 x + 1
    5·1 answer
  • What is the smallest of the whole number primitives that can represent the decimal value 333?
    15·1 answer
  • How many red beads will Elena need to make<br> 16 bracelets?
    11·1 answer
  • The differece of twice <br> a number and five is<br> three. Find the number
    8·2 answers
  • The cone shaped storage tank has a height=14 feet respectively.Find the volume of liquid the tank can hold.Round your answer to
    12·1 answer
  • Which one? Please be honest.
    6·1 answer
  • Please answer the question quickly
    6·1 answer
  • What is the area of this figure?<br><br> Enter your answer in the box.
    12·1 answer
  • What is the value of x
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!