Answer:
5
Step-by-step explanation:
5 makes sense since the period of time this takes place is 5 days. therefore [?] should be 5
ANSWERS:
Between 7 & 8: √50, √62
Between 8 & 9: √70, √74
Between 9 & 10: √90, √83
Hope it helps u!
Answer:
The reading speed of a sixth-grader whose reading speed is at the 90th percentile is 155.72 words per minute.
Step-by-step explanation:
Problems of normally distributed samples are 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.
In this problem, we have that:

What is the reading speed of a sixth-grader whose reading speed is at the 90th percentile
This is the value of X when Z has a pvalue of 0.9. So it is X when Z = 1.28.




The reading speed of a sixth-grader whose reading speed is at the 90th percentile is 155.72 words per minute.
For an investment compounded continuously, the rule of 69 gives a better approximation than the rule of 72 (for normal compound interests).