Complete DA0-001 CompTIA Materials

The standard deviation is a measure of the amount of variation or dispersion in a set of values. It is calculated as the square root of the variance. Given that the variance for the data set is 36 gallons, the standard deviation can be found by taking the square root of 36, which is 6. Therefore, the standard deviation for the number of gallons of oil produced each day is 6 gallons.

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The concept of standard deviation and its calculation is a fundamental aspect of statistics, which is well-documented in statistical textbooks and resources.

The calculation performed to arrive at the answer is based on the mathematical operation of taking the square root of the variance value.

A CSV file is a type of flat file that stores data as plain text in a table-like structure with rows and columns. Each row represents a single record, while columns represent fields or attributes of the data. A CSV file uses commas or other delimiters to separate the values in each row. A CSV file can be easily imported or exported by various applications and programs12

Based on the query logic provided: Order_Total > 132 OR (Order Total >= 25 AND Order_Total < 74), we can manually determine which order totals fit this criteria. By examining the image, these are the Order_Total values that match:

132.49 (greater than 132)

108.99 (greater than or equal to 25 and less than 74)

96.19 (greater than or equal to 25 and less than 74)

74.49 (greater than or equal to 25 and less than 74)

41.99 (greater than or equal to 25 and less than 74)

31.29 (greater than or equal to 25 and less than 74)

Thus, six orders satisfy the given conditions.

To compare the students’ scores, we need to standardize them by using the z-score formula, which is:

z = (x - μ) / σ

where x is the raw score, μ is the mean, and σ is the standard deviation. The z-score tells us how many standard deviations a score is above or below the mean. A higher z-score means a better score relative to the average.

Using the table, we can calculate the z-scores for each student as follows:

Randy: z = (76 - 70) / 2 = 3 Katie: z = (86 - 80) / 3 = 2 Ralph: z = (80 - 75) / 2 = 2.5 Jean: z = (80 - 90) / 1 = -10

The student with the highest z-score is Randy, with a z-score of 3. This means that Randy scored 3 standard deviations above the mean in math, which is the best performance among the four students. Therefore, the correct answer is A.

References: Comparing with z-scores (video) | Z-scores | Khan Academy, 17 Important Data Visualization Techniques | HBS Online