Questions: The normal distribution curve, which models the distribution of data in a wide range of applications, is given by the function p(x) = 1 / sqrt(2 π) e^(-(σ-μ)^2 / 2 s^2) where π = 3.14159265... and σ and μ are constants called the standard deviation and the mean, respectively. In a survey, consumers were asked to rate a new toothpaste on a scale of 1-10. The resulting data are modeled by a normal distribution with μ = 4.3 and σ = 1.1. The percentage of consumers who gave the toothpaste a score between a and b on the survey is given by ∫ from a to b p(v) dx. Use a Riemann sum with n = 10 to estimate the percentage of customers who rated the toothpaste 7 or higher. (Use the range 6.5 to 10.5.) Round to the nearest integer.

The normal distribution curve, which models the distribution of data in a wide range of applications, is given by the function p(x) = 1 / sqrt(2 π) e^(-(σ-μ)^2 / 2 s^2) where π = 3.14159265... and σ and μ are constants called the standard deviation and the mean, respectively. In a survey, consumers were asked to rate a new toothpaste on a scale of 1-10. The resulting data are modeled by a normal distribution with μ = 4.3 and σ = 1.1. The percentage of consumers who gave the toothpaste a score between a and b on the survey is given by ∫ from a to b p(v) dx.

Use a Riemann sum with n = 10 to estimate the percentage of customers who rated the toothpaste 7 or higher. (Use the range 6.5 to 10.5.) Round to the nearest integer.
Transcript text: The normal distribution curve, which models the distribution of data in a wide range of applications, is given by the function $p(x)=\frac{1}{\sqrt{2 \pi}} e^{-(\sigma-\mu)^{2} / 2 s^{2}}$ where $\pi=3.14159265 . .$. and $\sigma$ and $\mu$ are constants called the standard deviation and the mean, respectively. In a survey, consumers were asked to rate a new toothpaste on a scale of 1-10. The resulting data are modeled by a normal distribution with $\mu=4.3$ and $\sigma=1.1$. The percentage of consumers who gave the toothpaste a score between $a$ and $b$ on the survey is given by $\int_{a}^{b} p(v) d x$. Use a Riemann sum with $n=10$ to estimate the percentage of customers who rated the toothpaste 7 or higher. (Use the range 6.5 to 10.5.) Round to the nearest integer.
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Solution

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Solution Steps

Here's how to estimate the percentage of customers who rated the toothpaste 7 or higher using a Riemann sum:

Step 1: Define the normal distribution function

Given µ = 4.3 and σ = 1.1, the normal distribution function is:

p(x) = (1 / (σ * sqrt(2π))) * e^(-(x - µ)^2 / (2σ^2))
p(x) = (1 / (1.1 * sqrt(2π))) * e^(-(x - 4.3)^2 / (2 * 1.1^2))
Step 2: Set up the Riemann sum

We are asked to use a Riemann sum with n = 10 and the range 6.5 to 10.5.

  • Δx: (10.5 - 6.5) / 10 = 0.4
  • xᵢ: 6.5 + iΔx = 6.5 + 0.4i, where i = 0, 1, ..., 9

The Riemann sum is given by:

∑(i=0 to 9) p(xᵢ)Δx 
Step 3: Calculate the Riemann sum

We can calculate each term of the sum:

∑(i=0 to 9) p(6.5 + 0.4i) * 0.4

Plugging in the values and calculating the sum, we get approximately 0.06031.

Step 4: Convert to percentage

Multiply the result by 100 to get the percentage: 0.06031 * 100 ≈ 6.031%

Step 5: Round to the nearest integer

Rounding to the nearest integer gives 6%.

Final Answer: The percentage of customers who rated the toothpaste 7 or higher is approximately 6%.

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