6th grade math help me plzz
1 answer:
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Answer:
There is a 95% chance that values will be within ±2 standard deviations of the mean.
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 z-score 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 p-value, we get the probability that the value of the measure is greater than X.
The Empirical Rule states that, for a normally distributed random variable:
Approximately 68% of the measures are within 1 standard deviation of the mean.
Approximately 95% of the measures are within 2 standard deviations of the mean.
Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this question:
According to the empirical rule, 95% of the measures are within 2 standard deviations of the mean. So the correct statement is:
There is a 95% chance that values will be within ±2 standard deviations of the mean.
Well, we know the cyclist left the western part going eastwards, at the same time the car left the eastern part going westwards
the distance between them is 476 miles, and they met 8.5hrs later
let's say after 8.5hrs, the cyclist has travelled "d" miles, whilst the car has travelled the slack, or 476-d, in the same 8.5hrs
we know the rate of the car is faster... so if the cyclist rate is say "r", then the car's rate is r+33.2
thus
solve for "r", to see how fast the cyclist was going
what about the car? well, the car's rate is r + 33.2
the distance between them is 476 miles, and they met 8.5hrs later
let's say after 8.5hrs, the cyclist has travelled "d" miles, whilst the car has travelled the slack, or 476-d, in the same 8.5hrs
we know the rate of the car is faster... so if the cyclist rate is say "r", then the car's rate is r+33.2
thus
solve for "r", to see how fast the cyclist was going
what about the car? well, the car's rate is r + 33.2