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
vladimir1956 [14]
2 years ago
13

Batteries produced by a manufacturing company have had a life expectancy of 135 hours. Because of an improved production process

, the company believes that there has been an increase in the life expectancy of its batteries. A sample of 42 batteries showed an average life of 140 hours. From past information it is known the standard deviation of the population is 24 hours. Test to determine whether there has been an increase in the life expectancy of batteries. What is the test statistic and what conclusion can be made at the.10 level of significance? a. z =.208; Do not reject the null hypothesis b. z =.088; Do not reject the null hypothesis c. z = 1.35; Reject the null hypothesis d. z = 2.33; Reject the null hypothesis
Mathematics
1 answer:
Nikolay [14]2 years ago
5 0

Answer:  c. z = 1.35; Reject the null hypothesis

Step-by-step explanation:

Let \mu be the average life expectancy of its batteries.

As per given , we have

Null hypothesis : H_0 : \mu =135

Alternative hypothesis : H_a : \mu >135

Since H_a is right-tailed and population standard deviation is also known, so we perform right-tailed z-test.

Test statistic : \dfrac{\overlien{x}-\mu}{\dfrac{\sigma}{\sqrt{n}}}

where, n= sample size

\overlien{x}= sample mean

\mu= Population mean

\sigma=population standard deviation

For n=42,\ \overline{x}=140\ \&\ \sigma=24, we have

z=\dfrac{140-135}{\dfrac{24}{\sqrt{42}}}=1.35015431217\approx1.35

Critical one-tailed test value for 0.10 significance level :

z_{0.1}=1.28

 Decision : Since critical z value (1.28) < test statistic (1.35), so we reject the null hypothesis .

[When critical value is less than the test statistic value , we reject the null hypothesis .]

You might be interested in
How to find the volume of a triangular prisim
aleksandrvk [35]

Answer:

V=1

4h﹣a4+2(ab)2+2(ac)2﹣b4+2(bc)2﹣c4

Step-by-step explanation:

7 0
3 years ago
Read 2 more answers
Drag steps in the given order to evaluate this expression. (−3)(2)−7(−3)−10
patriot [66]
Step 1:
 
Multiply the numbers in parentheses:
 (-3 * 2) - (7 * (- 3)) - 10
 -6 - (- 21) -10
 Step 2:
 
Equal signs are added:
 -6 + 21-10
 Step 3:
 
Make the algebraic sum:
 -6 + 21-10 = 5
 Answer:
 
the final result is 5.
8 0
2 years ago
Read 2 more answers
I need help with this math problem ASAP please an explanation too
Rufina [12.5K]

Answer:

the answer is 300

Step-by-step explanation:

4 0
2 years ago
1 + 4 = 5<br> 2 + 5 = 12<br> 3 + 6 = 21<br> 8 + 11 = ?
AnnZ [28]
The answer of 8+11=40
7 0
2 years ago
Read 2 more answers
Find the measure of arc DF in degrees, given that the shaded region has an area of 45.27 square centimeters. If necessary, round
marishachu [46]
\bf \textit{area of a sector of a circle}\\\\&#10;A=\cfrac{\theta \pi r^2}{360}\qquad &#10;\begin{cases}&#10;r=radius\\&#10;\theta =angle\ in\\&#10;\qquad degrees\\&#10;----------\\&#10;r=6\\&#10;A=45.27&#10;\end{cases}\implies 45.27=\cfrac{\theta\pi \cdot 6^2}{360}&#10;\\\\\\&#10;45.27\cdot 360=\theta \pi 6^2\implies \cfrac{45.27\cdot 360}{36\pi }=\theta&#10;\\\\\\&#10;144.09888547540\approx\theta \implies  144.10^o\approx\theta =\widehat{DF}&#10;\\\\\\&#10;\textit{now, that gives you the central angle, however}\qquad \theta =\widehat{DF}

bearing in mind that, arcs get their angle measurement from the central angle they're in.  Thus, the measure of that central angle, is the same measure in degrees of that arcDF.
3 0
3 years ago
Other questions:
  • In 1989, Dutch ice skater Dries van Wijhe skated 200 km at an average speed of 35.27 km/h. How long was he skating? Use the form
    9·2 answers
  • Which is a function represented by the table
    12·1 answer
  • What is the Mean medium and mode 1 2 2 2 3 4 4
    5·2 answers
  • Question 7 (Worth 5 points)
    10·2 answers
  • Help me please and sorry for all of the questions.
    13·2 answers
  • Show that 6x^2+17x-39=0
    5·1 answer
  • A 99% confidence interval (in inches) for the mean height of a population is 65.7 &lt; μ &lt; 67.3. This result is based on a sa
    6·1 answer
  • 5(x – 4) + 3x – 9x = 6 - (2x + 5) + 8x
    7·1 answer
  • A line passes through the points (7, -5) and (3, 1). Determine the slope of the line.
    11·1 answer
  • Please do not claim this unless you answer the question.
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!