0 0.89 201 Use the TI-84 calculator to find the area of the shaded region.
The Correct Answer and Explanation is:
To find the area of the shaded region on a TI-84 calculator, based on the input “0 0.89 201,” we assume that:
- The lower bound of integration is 0
- The upper bound of integration is 0.89
- The function is the standard normal distribution, where 201 refers to the normal cumulative area (z = 0.89)
✅ Correct Answer:
Using the TI-84:
- Press 2nd then VARS to access the DISTR menu.
- Choose option 2:normalcdf(
- Enter the values: scssCopyEdit
normalcdf(0, 0.89, 0, 1)This inputs:- Lower bound = 0
- Upper bound = 0.89
- Mean = 0 (standard normal)
- Standard deviation = 1
- Press ENTER
📌 Result:
scssCopyEditnormalcdf(0, 0.89, 0, 1) ≈ 0.3133
✅ Final Answer:
The area of the shaded region is approximately 0.3133
📘 Textbook-Style Explanation
In statistics and probability, the area under a normal curve represents the probability or proportion of values falling within a certain range. The standard normal distribution has a mean (μ) of 0 and a standard deviation (σ) of 1. This question asks for the area under the standard normal curve from z = 0 to z = 0.89.
To calculate this on a TI-84 calculator, we use the normalcdf (cumulative distribution function), which computes the area under the normal curve between two z-values. The syntax is:
luaCopyEditnormalcdf(lower bound, upper bound, μ, σ)
Since this is a standard normal curve, μ = 0 and σ = 1. We input:
scssCopyEditnormalcdf(0, 0.89, 0, 1)
This command instructs the calculator to find the area from z = 0 to z = 0.89. Pressing ENTER returns approximately 0.3133, meaning that about 31.33% of the data falls between these two z-values.
This shaded region often represents a probability or proportion in a real-world context. For example, if scores on a test are normally distributed, 31.33% of students scored between the mean and 0.89 standard deviations above the mean.
Using graphing calculators like the TI-84 simplifies statistical analysis by providing accurate results without needing tables or complex formulas.
