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An insurance policy costs \(\$ 100\) and will pay policyholders \(\$ 10,000\) if they suffer a major injury (resulting in hospitalization) or \(\$ 3000\) if they suffer a minor injury (resulting in lost time from work). The company estimates that each year 1 in every 2000 policyholders may have a major injury, and 1 in 500 a minor injury only. a. Create a probability model for the profit on a policy. b. What's the company's expected profit on this policy? c. What's the standard deviation?

Short Answer

Expert verified
The probability model for profit is: No injury with probability 0.9975, profit of $100. Minor injury with probability 0.002, profit of -$2900. Major injury with probability 0.0005, profit of -$9900. The expected profit on the policy is $70.5. To get the standard deviation, compute the variance and take its square root.

Step by step solution

01

Establish a Probability Model

The profit from an insurance policy depends on the costs and the income. The cost is the payout for injuries and the income is the policy price, which is $100 every year. Three scenarios are possible in a year: no injury, minor injury, or major injury. The chance of no injury is not given, but it is computed as the complement to the total probability of an occurrence, which is \(1-(1/2000+1/500)\). Hence, the probability model for profit is as follows: No injury with probability \(1-(1/2000+1/500)=0.9975\), profit of $100. Minor injury with probability \(1/500=0.002\), profit of $100-$3000= -$2900. Major injury with probability \(1/2000=0.0005\), profit of $100-$10000= -$9900.
02

Calculate the Expected Profit

A company's expected profit is the sum of possible profits multiplied by their probabilities. This gives us an expected profit of \((0.9975)*100 + (0.002)*(-2900) + (0.0005)*(-9900) = $70.5\).
03

Calculate the Standard Deviation

First, calculate the variance, which requires each result's squared difference from the mean. Variance is given by: \(Var = [(100-70.5)^2 * 0.9975] + [(-2900-70.5)^2*0.002] + [(-9900-70.5)^2*0.0005]\). Then, the standard deviation is the square root of the variance, \(SD = \sqrt{Var}\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Understanding Expected Profit
Expected profit is a fundamental concept in both business and probability theory, acting as a predictive indicator of potential financial performance. It is calculated by multiplying each possible outcome by its probability and then summing these values. In terms of an insurance company, the expected profit would be the average amount the company anticipates to make on an insurance policy.

For instance, to determine the expected profit for our particular insurance policy, we used the formula: \( \text{Expected Profit} = (Prob_{\text{No Injury}} \times \text{Profit}_{\text{No Injury}}) + (Prob_{\text{Minor Injury}} \times \text{Profit}_{\text{Minor Injury}}) + (Prob_{\text{Major Injury}} \times \text{Profit}_{\text{Major Injury}}) \). With the probabilities provided for minor and major injuries, and the complement rule to find the probability for no injury, we succeed in calculating the expected profit of $70.5. This value aids the insurance company in pricing their policies to ensure profitability over time.
Standard Deviation in Profit Models
Standard deviation is a measure of the amount of variation or dispersion around an average, depicting how much individual data points differ from the mean. In the probability model for the insurance policy, we are looking at how profits can fluctuate around the expected profit.

The standard deviation helps the insurance company understand the risk involved with the policy. Step 3 of our calculation involved first finding the variance (the average of the squared differences from the Expected Profit) and then taking its square root to reach the standard deviation. The higher the standard deviation, the more risk (higher potential for varying profit) the insurer is taking on with the policy. This measurement is crucial in risk management for the insurance sector as companies aim to maintain profits while mitigating financial unpredictability.
Variance Calculation and Its Significance
Variance is another core concept in statistics, quantifying the spread between numbers in a data set, which in our case, is the spread of profits from different outcomes of an insurance policy. A high variance indicates that the numbers are far from the mean and each other, while a low variance indicates the opposite.

To calculate the variance (as shown in Step 3), we use the equation: \( \text{Variance} = \text{Var} = \text{Sum of} [(X - \text{Expected Profit})^2 \times \text{Prob}(X)] \), where 'X' represents the profits in each scenario. By squaring the differences from the mean, we emphasize larger differences – a vital consideration for financial decision-making. For the insurance company, understanding variance is essential, as it pertains to their risk of experiencing significantly different actual profits compared to what they expected, based on their policy pricing and the probabilities of claim events occurring.

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