<h3>
Answer: 50</h3>
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Explanation:
We simply multiply the two values given to us
600*(1/12) = 600/12 = 50
We expect about 50 bulbs to be defective.
Note how if we had 50 bad bulbs, then 50/600 = (1*50)/(12*50) = 1/12 of the batch of 600 bulbs is defective.
Answer:
correct
Step-by-step explanation:
i think correct,but maybe i am wrong
Answer:
Mean = 78.2
Standard deviation = 5.8
Step-by-step explanation:
Mathematically z-score;
= (x-mean)/SD
From the question;
12% of test scores were above 85
Thus;
P( x > 85) = 12%
P(x > 85) = 0.12
Now let’s get the z-score that has a probability of 0.12
This can be obtained from the standard normal distribution table and it is = 1.175
Thus;
1.175 = (85 - mean)/SD
let’s call the mean a and the SD b
1.175 = (85-a)/b
1.175b = 85 - a
a = 85 - 1.175b ••••••••(i)
Secondly 8% of scores were below 70
Let’s find the z-score corresponding to this proportion;
We use the standard normal distribution table as usual;
P( x < 70) = 0.08
z-score = -1.405
Thus;
-1.405 =( 70-a)/b
-1.405b = 70-a
a = 70 + 1.405b ••••••(ii)
Equate the two a
70 + 1.405b = 85 - 1.175b
85 -70 = 1.405b + 1.175b
15 = 2.58b
b = 15/2.58
b = 5.81
a = 70 + 1.405b
a = 70 + 1.405(5.81)
a = 78.16
So mean = 78.2 and Standard deviation is 5.8
2:3:4 gives 9 equal parts.
1.20 divided by 9 is 0.133.
2 * 0.133 would be 0.266m
3 * 0.133 would be 0.399m
4 * 0.133 would be 0.533m
To check this calculate 0.533 + 0.399 + 0.266 would be 1.198m (close enough)
