8th-ed Chapter 09, Supplementary Exercises, Problem 110 The customers at a bank complained about long lines and the time they had to spend waiting for service. It is known that the customers at this bank had to wait 9 minutes, on average, before being served. The management made some changes to reduce the waiting time for its customers. A sample of 59 customers taken after these changes were made produced a mean waiting time of 8.1 minutes with a standard deviation of 2.5 minutes. Using this sample mean, the bank manager displayed a huge banner inside the bank mentioning that the mean waiting time for customers has been reduced by new changes. Do you think the bank manager's claim is justifiable? Use a 2.5% significance level to answer this question. Use both approaches. Use the p-value approach. Use the t distribution table to find a range for the p-value. Enter the exact values for the range. < p-value < Use the critical-value approach. Round your answers to three decimal places. Observed value = Critical value = Conclusion: The manager's claim true false SHOW HINT LINK TO TEXT
Addition Rule of Probability
It simply refers to the likelihood of an event taking place whenever the occurrence of an event is uncertain. The probability of a single event can be calculated by dividing the number of successful trials of that event by the total number of trials.
Expected Value
When a large number of trials are performed for any random variable ‘X’, the predicted result is most likely the mean of all the outcomes for the random variable and it is known as expected value also known as expectation. The expected value, also known as the expectation, is denoted by: E(X).
Probability Distributions
Understanding probability is necessary to know the probability distributions. In statistics, probability is how the uncertainty of an event is measured. This event can be anything. The most common examples include tossing a coin, rolling a die, or choosing a card. Each of these events has multiple possibilities. Every such possibility is measured with the help of probability. To be more precise, the probability is used for calculating the occurrence of events that may or may not happen. Probability does not give sure results. Unless the probability of any event is 1, the different outcomes may or may not happen in real life, regardless of how less or how more their probability is.
Basic Probability
The simple definition of probability it is a chance of the occurrence of an event. It is defined in numerical form and the probability value is between 0 to 1. The probability value 0 indicates that there is no chance of that event occurring and the probability value 1 indicates that the event will occur. Sum of the probability value must be 1. The probability value is never a negative number. If it happens, then recheck the calculation.
8th-ed Chapter 09, Supplementary Exercises, Problem 110
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