Question

Brand X batteries have a mean life span of 102 hours, with a standard deviation of 6.8 hours. Brand Y batteries have a mean life span of 100 hours, with a standard deviation of 1.4 hours. Complete each of the sentences.

Answer 1

Answer:

Step-by-step explanation:

Hello!

X₁: Life span of a battery of Brand X

X₁~N(μ₁;σ₁²)

μ₁= 102hours

σ₁= 6.8hours

X₂: Life span of a battery of Brand Y

X₂~N(μ₂;σ²)

μ₂= 100hours

σ₂= 1.4hours

To complete the first two sentences, you have to use the empirical rule:

μ±δ= 68% of the distribution

μ±2δ= 95% of the distribution

μ±3δ= 99% of the distribution

1. About 68% of brand x’s batteries have a lifespan between 95.2 and 108.8 hours.

μ₁±σ₁= 102 ± 6.8= 95.2; 108.8

2. About 68% of brand y’s batteries have a lifespan between 98.6 and 101.4 hours.

μ₂±σ₂= 100 ± 1.4= 98.6; 101.4

3. The life span of brand Y ’s battery is more likely to be consistently close to the mean.

The standard deviations show you the dispersion of the distribution. A low standard deviation indicates that the values are close to the mean. A high standard deviation indicates that the values are further away the values are from the mean.

The standard deviation for the X batteries is σ₁= 6.8hours and the Y batteries are σ₂= 1.4hours since the standard deviation for the Y batteries is less than the standard deviation for the X batteries, you'd expect that the life span of the Y batteries will be closer to the mean than the life span of the X batteries.

I hope it helps!