Normal Distribution Empirical

The mean life of a tire is 30,000 km. The standard deviation is 2000 km.

Then, 68% of all tires will have a life between ___________ km and __________ km.

•  28,000 km and 32,000 km.

• 24,000 km and 34,000 km.

• 26,000 km and 34,000 km.

• 27,000 km and 31,000 km.

What is the area under the curve between z = 0 and z = 1.45?

• .9265

• .4265

• .4500

• .5000

What's the probability x < 13?

(Mean = 10, Variance = 4)

• 0.9332

• 0.2266

• 0.7734

• 0.0668

The center of the curve represents what value of a data set?

• μ

• δ

• Σ

• Ζ

What is the area under the curve to the left of z = 0.55 ?

• .2912

• .5500

• .9394

• .7088

What is the total area under the curve?

• 1
• .9998
• .997
• -3 < z < 3

Given a mean of 75 and a standard deviation of 7, what percentage of scores are between 75 and 82?

• 68%

• 81.5%

• 16%

• 34%

According to the empirical rule, what percentage of data falls within 1 standard deviation of the mean?

• 25%

• 68%

• 95%

• 99.7%

The average weight of a newborn is 7.5 pounds, with a standard deviation of 1.25 pounds. Birth weight follows the standard normal curve. What percent of newborns weigh 5 pounds or less at birth?

• 2.35%

• 0.15%

• 2.5%

• 50%

The normal curve is symmetrical about the mean.

• True

• False