The daily stock price for International Business Machines (IBM) historically has followed an approximately normal distribution (when adjusting for inflation) with a mean of $143.311 and standard deviation of $3.9988 Approximately 38.34% of days IBM had a stock price greater than what dollar amount

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Answer:

Greater than $144.49.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

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.

Mean of $143.311 and standard deviation of $3.9988.

This means that [tex]\mu = 143.311, \sigma = 3.9988[/tex].

Approximately 38.34% of days IBM had a stock price greater than what dollar amount?

Greater than X when Z has a p-value of 1 - 0.3834 = 0.6166, so X when Z = 0.295.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]0.295 = \frac{X - 143.311}{3.9988}[/tex]

[tex]X - 143.311 = 0.295*3.9988[/tex]

[tex]X = 144.49[/tex]

Greater than $144.49.