Answer:
a) The mean is 
b) The standard deviation is 
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
The probability a student selected at random takes at least 55.50 minutes to complete the examination equals 0.6915.
This means that when X = 55.5, Z has a pvalue of 1 - 0.6915 = 0.3085. This means that when 
So




The probability a student selected at random takes no more than 71.52 minutes to complete the examination equals 0.8997.
This means that when X = 71.52, Z has a pvalue of 0.8997. This means that when 
So




Since we also have that 





Question
The mean is 
The standard deviation is 
Answer:
its side CE
Step-by-step explanation:
I got it wrong and it showed me the answer. Hope this helps!
Answer:
Step-by-step explanation:
1. There will be 9 roses in total.
Probability Orange: 2/9
Probability Yellow: 3/9 = ⅓
Probability Pink: 4/9
2. 4/7 as there are 7 bowls in total and 4 are chocolate.
3. 4/10 = ⅖ (simplified) There are 10 fruits in total and 4 are apples.
4. 5/15 = ⅓ (simplified) There are 15 cars in total and 5 or them are cooper minis.
5. 2/6 = ⅓ (simplified) There are 6 textbooks and 2 of them are math.
6. 13/20 There are 20 drinks and 13 of them are lemonade.
7. There are 10 toys in total.
Probability toy cars: 3/10
Probability dolls: 2/10 = ⅕ (simplified)
Probability balls: 5/10 = ½ (simplified)
8. In total the number of red roses and lilies are 7. There are 10 flowers in total so the number of jasmines are 3. Therefore the probability of getting a jasmine is 3/10
9. 20/50 = ⅖ (simplified) There are 50 papers in total and 20 of them are yellow.
10. 8/18 = 4/9 (simplified) There are 18 buses and 8 of them are air conditioned.
Answer:
D
Step-by-step explanation:
Plug in and see.
Check A: Lets plug in (0,3) into y<2/3 x+2.
3<2/3 (0)+2
3<2 is not true so not A
Check C: Lets plug in (3,5) into y<2/3 x+2.
5<2/3 (3)+2
5<2+2
5<4 is not true so not C
Check B: Lets plug in (-3,1) into y<2/3 x+2.
1<2/3 (-3)+2
1<0 is not true so not B
Check D: Lets plug in (1,2) into y<2/3 x+2.
2<2/3 (1)+2
2<2/3+2 is true so D