The daily exchange rates for the five-year period 2003 to 2008 between currency A and currency B are well modeled by a normal distribution with mean 1.832 in currency A (to currency B) and standard deviation 0.044 in currency A. Given this model, and using the 68-95-99.7 rule to approximate the probabilities rather than using technology to find the values more precisely, complete parts (a) through (d). a) What would the cutoff rate be that would separate the highest 2.5 % of currency A/currency B rates?

The cutoff rate that would separate the highest 2.5 % of currency A/currency B rates is 1.92.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

68% of the measures are within 1 standard deviation of the mean.

95% of the measures are within 2 standard deviation of the mean.

99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean = 1.832

Standard deviation = 0.044

Top 2.5%

95% of the measures are within 2 standard deviation of the mean.

Since the normal distribution is symmetric, this 95% goes from the 50 - 95/2 = 2.5th percentile to the 50 + 95/2 = 97.5th percentile.

The 97.5th percentile is the cutoff for the highest 2.5% of currency A/currency B rates, and it is 2 standard deviations above the mean.

1.832 + 2*0.044 = 1.92

The cutoff rate that would separate the highest 2.5 % of currency A/currency B rates is 1.92.