PLEASE HELP ASAP FOR TEST

The quality control manager at a light bulb factory needs to estimate the mean life of a batch (population) of light bulbs. We a

Nadusha1986 [10]

Answer:

a)95% confidence intervals for the population mean of light bulbs in this batch

(325.5 ,374.5)

b)

The calculated value Z = 4 > 1.96 at 0.05 level of significance

Null hypothesis is rejected

The manufacturer has not right to take the average life of the light bulbs is 400 hours.

Step-by-step explanation:

Given sample size n = 64

Given mean of the sample x⁻ = 350

Standard deviation of the Population σ = 100 hours

The tabulated value Z₀.₉₅ = 1.96

95% confidence intervals for the population mean of light bulbs in this batch

$(x^{-} - Z_{\frac{\alpha }{2} } \frac{S.D}{\sqrt{n} } , x^{-} + Z_{\frac{\alpha }{2} }\frac{S.D}{\sqrt{n} } )$

$(350 - 1.96\frac{100}{\sqrt{64} } , 350 + 1.96\frac{100}{\sqrt{64} } )$

$(350 -24.5, 350 +24.5)$

(325.5 ,374.5)

b)

Explanation:-

Given mean of the Population μ = 400

Given sample size n = 64

Given mean of the sample x⁻ = 350

Standard deviation of the Population σ = 100 hours

Null hypothesis : H₀:The manufacturer has right to take the average life of the light bulbs is 400 hours.

μ = 400

Alternative Hypothesis: H₁: μ ≠400

The test statistic

$Z = \frac{x^{-}-mean }{\frac{S.D}{\sqrt{n} } }$

$Z = \frac{350 -400}{\frac{100}{\sqrt{64} } }$

|Z| = |-4|

The tabulated value Z₀.₉₅ = 1.96

The calculated value Z = 4 > 1.96 at 0.05 level of significance

Null hypothesis is rejected.

Conclusion:-

The manufacturer has not right to take the average life of the light bulbs is 400 hours.

5 0

2 years ago

Which of the following is an example of a null hypothesis? A. The average quantity of detergent put into a box by this filling m

gavmur [86]

Answer:

C

Step-by-step explanation:

Null hypothesis: hypthesis to test that there is no significant difference between the specific characteristic of a population. Analysts look to reject a null hypothesis

A. the shipping company's average delivery time is different from 3 days. This is an example of alternative hypothesis. Null hypothesis is writtien as a claim

B. This again is an example of alternate hypthesis. The claim that mean is 0.03 is rejected with the results

C. This is a claim

D. This is rejection of a claim that mean is 1 pound

E. This is rejection of claim that average delivery time is 3 days.

5 0

2 years ago

Solve for $a$: $3a-7(3-a)=5$. Express your answer as a common fraction in simplest form.

SashulF [63]

Answer:

2.6

Step-by-step explanation:

just put one part of the equation in y1 and the other in y2 and hit 2nd trace 5 an hit enter 4 times

then it will bring a graph hit enter 3 time again and it will show u the answer at the bottom left

3 0

2 years ago

Denise is constructing A square in which two of its vertices are points M and N. She has already used her straightedge and compa

yan [13]

Denise is constructing A square.

Note: A square has all sides equal.

We already given two vertices M and N of the square.

And another edge of the square is made by from N.

Because a square has all sides of equal length, the side NO should also be equal to MN side of the square.

Therefore, Denise need to place the point of the compass on point N and draw an arc that intersects N O, using MN as the width for the opening of the compass. That would make the NO equals MN.

Therefore, correct option is :

D) place the point of the compass on point N and draw an arc that intersects N O, using MN as the width for the opening of the compass.

6 0

2 years ago

Read 2 more answers

Adam is going to make concrete

hodyreva [135]

Answer:

90 kg of stone

Step-by-step explanation:

Adam has 8 x 25 = 200

19 x 22.5 = 427.5

20 x 50 = 1000

He has enough cement and sand

He needs 1090 - 1000 = 90 kg of stone

He needs 2 bags of stone

5 0

2 years ago