The average number of red blood cells in an adult male is 6.2 million cells per microliter, with a standard deviation of 0.6 million cells per microliter. If Sergio’s blood contains 6.7 million cells per microliter, which option correctly calculates and interprets his z-score?(1 point)
Responses
Sergio’s red blood cell count is 0.833 standard deviations below the mean.
Sergio’s red blood cell count is 0.833 standard deviations below the mean.
Sergio’s red blood cell count is 0.5 standard deviations above the mean.
Sergio’s red blood cell count is 0.5 standard deviations above the mean.
Sergio’s red blood cell count is 0.833 standard deviations above the mean.
Sergio’s red blood cell count is 0.833 standard deviations above the mean.
Sergio’s red blood cell count is 0.5 standard deviations below the mean.
Sergio’s red blood cell count is 0.833 standard deviations above the mean.
Given the mean of a data set is 254 and has a standard deviation of 12, which of the following data points would result in a z-score that indicates the data point is 2 standard deviations below the mean?(1 point)
Responses
230
230
24
24
278
278
19.167
Data point of 230 would result in a z-score that indicates the data point is 2 standard deviations below the mean.
Which of the following percentages accurately estimates the area under a normal curve to the left of a z-score of 1.23?(1 point)
Responses
89.07 percent
89.07 percent
0.8907 percent
0.8907 percent
10.93 percent
10.93 percent
0.1093 percent
89.07 percent accurately estimates the area under a normal curve to the left of a z-score of 1.23.
Which of the following percentages accurately estimates the area under a normal curve between a z-score of −0.11 and 2.43?(1 point)
Responses
53.63 percent
53.63 percent
45.62 percent
45.62 percent
54.38 percent
54.38 percent
99.25 percent
99.25 percent
54.38 percent accurately estimates the area under a normal curve between a z-score of -0.11 and 2.43.
Use the table to answer the question.
The top-left cell of a z-score table is labeled z. The remaining cells in the header row have values ranging from 0.00 to 0.09 in increments of 0.01. Below z, the first column has values ranging from negative 1.7 to negative 0.0 in increments of 0.1.
The mean temperature during the summer in a certain city is 80 degrees Fahrenheit, with a standard deviation of 5 degrees Fahrenheit. What is the probability that a randomly selected day has a temperature below 73 degrees Fahrenheit?
(1 point)
Responses
8.08%
8.08%
95.25
95.25
4.75%
4.75%
91.92%
To calculate this, we need to find the z-score for a temperature of 73 degrees Fahrenheit:
\[ z = \dfrac{X - \text{mean}}{\text{standard deviation}} = \dfrac{73 - 80}{5} = -1.4 \]
Looking at the z-score table, the closest z-score of -1.4 is between -1.4 and -1.3. The probability for z-score between -1.4 and -1.3 is approximately 0.0808 or 8.08%.
Therefore, the probability that a randomly selected day has a temperature below 73 degrees Fahrenheit is 8.08%.