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Phantasy [73]
3 years ago
9

NEED HELP ASAP laboratory tests show that the lives of light bulbs are normally distributed with a mean of 750 hours and a stand

ard deviation of 75 hours. find the probability that a randomly selected light bulb will last between 900 and 975 hours.
Mathematics
1 answer:
professor190 [17]3 years ago
8 0

Answer:

0.0214

Step-by-step explanation:

We can get these answer by finding the z-scores at first

Mathematically;

z-score = x-mean/sd

For 900;

z-score = 900-750/75 = 150/75 = 2

For 975

z-score = (975-750)/75 = 3

So the probability we want to calculate is;

P(2<x<3)

This can be calculated using the standard normal distribution table

From the standard score table;

P(2<x<3) = 0.0214

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sammy [17]

Answer:

9872.698 is 9.746 x 1013 in standard form

4 0
3 years ago
Bottles of a popular cola drink are supposed to contain 300 ml of cola. There is some variation from bottle to bottle because th
Ksju [112]

Answer:

We conclude that the mean contents of cola bottles is more than or equal to the advertised 300 ml.

Step-by-step explanation:

We are given that Bottles of a popular cola drink are supposed to contain 300 ml of cola. The distribution of the contents is normal with standard deviation of 3 ml.

A student who suspects that the bottler is under-filling measures the contents of six bottles. The results are: 299.4, 297.7, 301.0, 298.9, 300.2, 297.0

<u><em>Let </em></u>\mu<u><em> = mean contents of cola bottles.</em></u>

SO, Null Hypothesis, H_0 : \mu \geq  300 ml   {means that the mean contents of cola bottles is more than or equal to the advertised 300 ml}

Alternate Hypothesis, H_A : \mu < 300 ml   {means that the mean contents of cola bottles is less than the advertised 300 ml}

The test statistics that will be used here is <u>One-sample z test statistics</u> as we know about the population standard deviation;

                       T.S.  = \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n} } }  ~ N(0,1)

where, \bar X = sample mean contents of cola bottle = \frac{\sum X}{n} = 299.03 ml

            \sigma = population standard deviation = 3 ml

            n = sample of bottles = 6

So, <em><u>test statistics</u></em>  =  \frac{299.03-300}{\frac{3}{\sqrt{6} } }     

                               =  -0.792

<em>Now at 5% significance level, the z table gives critical value of -1.6449 for left-tailed test. Since our test statistics is more than the critical value of z as -0.792 > -1.6449, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which we fail to reject our null hypothesis.</em>

Therefore, we conclude that the mean contents of cola bottles is more than or equal to the advertised 300 ml.

8 0
3 years ago
Y=-1/4x +9 what is the slope and y - intercept
zvonat [6]
Well your slope is -1/4 and your y-intercept is 9
5 0
3 years ago
Read 2 more answers
Name FIVE x-values for which the tangent function equals 0.
beks73 [17]
0, pi, 2pi, 3pi, 4pi... Get the picture
5 0
3 years ago
For the people who helped me with the question
erik [133]

Answer:

glad my answer helped you.

Step-by-step explanation:

hope that because i showed the steps, it will help you if you come across a problem like that in the future too!

4 0
2 years ago
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