Pl mean of a set of normally distributed data is 600 with a standard deviation of 20. what percent of the data is between 580 and 620?

The percentage of the data between 580 and 620 is 68.26 %

Step-by-step explanation:

Given,

Mean, = 600,

Standard deviation, = 20,

Using the equation,

Z-score for the data 580 =

While, the z-score for the data 620 =

Using normal distribution table,

P(580 < z) = 0.1587

Also, P(620 > z) = 0.8413

Hence, the percent of the data is between 580 and 620 = P(620 > z)  - P(580 < z)

= 0.8413  - 0.1587

= 0.6826

= 68.26 %

let x be the money she spent so that she can earn the free t-shirt.

since, she already spent $112.49

⇒

also, as per the statement: jennifer must spend $250 or more in order to qualify for a free t-shirt at the store.

then,

we have an inequality i.,e

subtract 112.49 from both sides we get;

therefore, $137. 51 more money does jennifer need to spend so that she can earn the free t-shirt