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The table shows some information about the lifetimes, t, in hours, of some lightbulbs.

Lifetime Frequency
25 < t ≤ 50 76
50 < t ≤ 100 33
100 < t≤ 150 67
150 < t ≤ 200 28
200 < t ≤ 250 0
250 < t ≤ 300 82
300 < t≤ 350 36

Estimate the mean lifetime of a bulb.
Give your answer rounded to 2 DP.
Plz i need help with this answer quick plzzz

Answer :

MrRoyal

The mean lifetime of a bulb is 130.82

The table is given as:

Lifetime           Frequency

25 < t ≤ 50       76

50 < t ≤ 100      33

100 < t≤ 150      67

150 < t ≤ 200    28

200 < t ≤ 250    0

250 < t ≤ 300    82

300 < t≤ 350     36

Next, we calculate the mean of the intervals by:

[tex]x = \frac{x_1 + x_2}{2}[/tex]

For interval 25 < t ≤ 50, we have:

[tex]t = \frac{25 + 50}{2} = 37.5[/tex]

For interval 50 < t ≤ 100, we have:

[tex]t = \frac{50 + 100}{2} = 75[/tex]

Using the above formula, we have the new table to be:

Lifetime           Frequency

37.5                      76

75                      33

125                      67

175                      28

225                      0

275                      82

325                      36

The mean is then calculated as:

[tex]\bar x = \frac{\sum fx}{\sum f}[/tex]

So, we have:

[tex]\bar x = \frac{37.5 * 76 + 75* 33 + 125 * 67 + 175 *28 + 225*0 + 275* 82 + 325 *3}{76 + 33 + 67 + 28 + 0 + 82 + 36}[/tex]

Simplify

[tex]\bar x = \frac{42125}{322}[/tex]

Divide

[tex]\bar x = 130.82[/tex]

Hence, the mean lifetime of a bulb is 130.82

Read more about mean at:

https://brainly.com/question/14532771

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