Math Problem Statement

Use the data in the following​ table, which lists​ drive-thru order accuracy at popular fast food chains. Assume that orders are randomly selected from those included in the table. ​Drive-thru Restaurant
A B C D Order Accurate 330 278 238 127 Order Not Accurate 34 59 33 12 If two orders are​ selected, find the probability that they are both accurate. Complete parts​ (a) and​ (b) below. Question content area bottom Part 1 a. Assume that the selections are made with replacement. Are the events​ independent? The probability is . The events independent. ​(Do not round until the final answer. Round to four decimal places as​ needed.)

Solution

To answer the question about the probability of two orders being accurate with replacement, we first need to determine the following details:

Step 1: Calculate the total number of orders for each restaurant

For each restaurant, the total number of orders is the sum of accurate and inaccurate orders. The data for each restaurant is as follows:

  • Restaurant A:

    • Accurate Orders = 330
    • Not Accurate Orders = 34
    • Total Orders = 330 + 34 = 364
  • Restaurant B:

    • Accurate Orders = 278
    • Not Accurate Orders = 59
    • Total Orders = 278 + 59 = 337
  • Restaurant C:

    • Accurate Orders = 238
    • Not Accurate Orders = 33
    • Total Orders = 238 + 33 = 271
  • Restaurant D:

    • Accurate Orders = 127
    • Not Accurate Orders = 12
    • Total Orders = 127 + 12 = 139

Step 2: Find the probability of selecting an accurate order from each restaurant

The probability of selecting an accurate order from a specific restaurant is given by:

P(Accurate)=Accurate OrdersTotal OrdersP(\text{Accurate}) = \frac{\text{Accurate Orders}}{\text{Total Orders}}

Now, let's compute the probability for each restaurant:

  • Restaurant A: PA(Accurate)=3303640.9074P_A(\text{Accurate}) = \frac{330}{364} \approx 0.9074

  • Restaurant B: PB(Accurate)=2783370.8263P_B(\text{Accurate}) = \frac{278}{337} \approx 0.8263

  • Restaurant C: PC(Accurate)=2382710.8775P_C(\text{Accurate}) = \frac{238}{271} \approx 0.8775

  • Restaurant D: PD(Accurate)=1271390.9136P_D(\text{Accurate}) = \frac{127}{139} \approx 0.9136

Step 3: Assume selections are made with replacement

The probability that both selected orders are accurate is the product of the probabilities of selecting an accurate order in each selection. If selections are made with replacement, then the probability that both orders are accurate from any restaurant is simply:

P(Both Accurate)=P(Accurate)×P(Accurate)=P(Accurate)2P(\text{Both Accurate}) = P(\text{Accurate}) \times P(\text{Accurate}) = P(\text{Accurate})^2

Let's calculate the probability for each restaurant.

  • Restaurant A: PA(Both Accurate)=0.907420.8234P_A(\text{Both Accurate}) = 0.9074^2 \approx 0.8234

  • Restaurant B: PB(Both Accurate)=0.826320.6828P_B(\text{Both Accurate}) = 0.8263^2 \approx 0.6828

  • Restaurant C: PC(Both Accurate)=0.877520.7696P_C(\text{Both Accurate}) = 0.8775^2 \approx 0.7696

  • Restaurant D: PD(Both Accurate)=0.913620.8345P_D(\text{Both Accurate}) = 0.9136^2 \approx 0.8345

Step 4: Determine if the events are independent

For events to be independent, the probability of the combined event (two orders being accurate) must be the product of their individual probabilities. Since selections are being made with replacement, the events are independent because the second selection does not depend on the first.

Final Answer:

  • The probability is:

    • For Restaurant A: PA(Both Accurate)=0.8234P_A(\text{Both Accurate}) = 0.8234
    • For Restaurant B: PB(Both Accurate)=0.6828P_B(\text{Both Accurate}) = 0.6828
    • For Restaurant C: PC(Both Accurate)=0.7696P_C(\text{Both Accurate}) = 0.7696
    • For Restaurant D: PD(Both Accurate)=0.8345P_D(\text{Both Accurate}) = 0.8345
  • The events are independent.

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Math Problem Analysis

Mathematical Concepts

Probability
Events
Independent Events

Formulas

P(Accurate) = Accurate Orders / Total Orders
P(Both Accurate) = P(Accurate) * P(Accurate)

Theorems

Multiplication Rule for Independent Events

Suitable Grade Level

Grades 9-11