Answer:
a) 3354 seconds
b) 6294 seconds
Step-by-step explanation:
When the distribution is normal, we use 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.
(a) The cutoff time for the fastest 5% of athletes in the men's group, i.e. those who took the shortest 5% of time to finish.

The cutoff for the shortest 5% is the 5th percentile, which is X when Z has a pvalue of 0.05. So X when Z = -1.645.




Cutoff of 3354 seconds.
(b) The cutoff time for the slowest 10% of athletes in the women's group.

The slowest 10% is the 10% that takes more time, so the cutoff is the 100 - 10 = 90th percentile, which is X when Z has a pvalue of 0.9. So X when Z = 1.28.




Cutoff time of 6294 seconds
Answer:
D
Step-by-step explanation:
The adult meals cost 16$ and the student meals cost 8$. A=16 and S=8. 80•8= 640 you then take eight and multiply it by two and get 16 because it says the adult meals were twice as much. 45•16= 720.
640+720= 1360
Answer:
-99232
Step-by-step explanation:
PEMDAS
Solve in the brackets/parenthesis and expand out
4*9=36*3=108-12=96
Now we have (96)*8-10^5
Next up is exponents so -10^5 is -100000
Next is multiplication so (96)*8=768
Lastly is subtraction: 768-100000= -99232
Scientific notation of this answer is -9.9232*10^4 (depends which answer they are looking for)