How many times does 5 go into 3??
1 answer:
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Answer:
a) 86.73
b) 90.24
c) 10.56% scoring more than 90
d) 75.8
e) 50% probability that a randomly selected student will score more than 80.
Step-by-step explanation:
Problems of normally distributed samples 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.
In this problem, we have that:
a. Find the 80th percentile.
This is the value of X when Z has a pvalue of 0.8. So X when Z = 0.841.
b. Find the cutoff for the A grade if the top 10% get an A.
This is the value of X when Z has a pvalue of 0.9. So X when Z = 1.28.
c. Find the percentage scoring more than 90.
This is 1 subtracted by the pvalue of Z when X = 90. So
has a pvalue of 0.8944.
1 - 0.8944 = 0.1056
10.56% scoring more than 90
d. Find the score that separates the bottom 30% from the top 70%.
This is the value of X when Z has a pvalue of 0.3. So X when Z = -0.525.
e. Find the probability that a randomly selected student will score more than 80.
This is 1 subtracted by the pvalue of Z when X = 80.
has a pvalue of 0.5.
1 - 0.5 = 0.5
50% probability that a randomly selected student will score more than 80.
Answer:
D. x=29.37
Step-by-step explanation:
To answer this question you have to understand how log work. Log is the abbreviation of logarithm and it works as an inverse function of exponentiation.
The rules should be like this:
Variable a in the equation is called base. If it left empty you can assume its base 10. The log in this question using 5 as a base. Variable b will be x and variable c will be 2.1
Now, let's change the variable of the equation using the information from the question.