Question

karen is trying to analyze the grades shes earned so far this year. she already translated the grades from their letters. 3, 3, 3.3, 2, 3.3, 3, 1, 3, 1, 1, 4, 4, 3.3, 3, 2 guided practice mean x = 2.42 = 39.9 median 4.5 = 242 mode

Explanation:

Step1: Calculate the sum of grades

The grades are 3, 3, 3.3, 2, 3.3, 3, 1, 3, 1, 1, 4, 4, 3.3, 3, 2. The sum is $3 + 3+3.3 + 2+3.3+3+1+3+1+1+4+4+3.3+3+2=39.9$. There are $n = 15$ grades.

Step2: Calculate the mean

The mean $\bar{x}=\frac{\sum_{i = 1}^{n}x_{i}}{n}=\frac{39.9}{15}=2.66$.

Step3: Arrange grades in ascending order

$1,1,1,2,2,3,3,3,3,3,3.3,3.3,3.3,4,4$. Since $n = 15$ (odd - numbered data set), the median is the $(\frac{n + 1}{2})$ - th value. $\frac{15+1}{2}=8$ - th value, so the median is 3.

Step4: Find the mode

The mode is the value that appears most frequently. The number 3 appears 5 times, more frequently than any other number, so the mode is 3.

Answer:

Mean: 2.66
Median: 3
Mode: 3