Answer:
0.5981 = 59.81% probability that three or less of the selected adults have saved nothing for retirement
Step-by-step explanation:
For each adult, there are only two possible outcomes. Either they save nothing for retirement, or they save something. The probability of an adult saving nothing for retirement is independent of any other adult. This means that the binomial probability distribution is used to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
In which is the number of different combinations of x objects from a set of n elements, given by the following formula.
And p is the probability of X happening.
20% of adults in the United States save nothing for retirement (CNBC website).
This means that
Suppose that sixteen adults in the United States are selected randomly.
This means that
What is the probability that three or less of the selected adults have saved nothing for retirement?
This is:
In which
0.5981 = 59.81% probability that three or less of the selected adults have saved nothing for retirement
19.95x + 9.95y <== ur answer
Answer:
7/11
Step-by-step explanation:
This is the only fraction without a 1 in its numerator.
Answer:
The minimum score required for an A grade is 88.
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:
Find the minimum score required for an A grade.
Top 12%, which is at least the 100-12 = 88th percentile, which is the value of X when Z has a pvalue of 0.88. So it is X when Z = 1.175.
Rounding to the nearest whole number
The minimum score required for an A grade is 88.