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### Calculating Mean for Discrete Data

1. Write down the formula to calculate the mean for discrete data.

[tex]\[
\text{Mean} = \frac{\Sigma fx}{N}
\][/tex]

2. Calculate the mean given [tex]\(\Sigma fx = 1620\)[/tex] and [tex]\(N = 36\)[/tex].

[tex]\[
\text{Mean} = \frac{1620}{36}
\][/tex]

3. If 6 observations are removed, what would be the new mean?

- Calculate the new total number of observations: [tex]\(N - 6\)[/tex].
- Calculate the new [tex]\(\Sigma fx\)[/tex] if needed, otherwise assume the same total for simplicity.
- Compute the new mean using the formula:

[tex]\[
\text{New Mean} = \frac{\Sigma fx}{N - 6}
\][/tex]

4. If 180 is added to the original [tex]\(\Sigma fx\)[/tex], by what percentage will the mean increase?

- Calculate the new [tex]\(\Sigma fx\)[/tex]:

[tex]\[
\Sigma fx_{\text{new}} = 1620 + 180
\][/tex]

- Calculate the new mean:

[tex]\[
\text{New Mean} = \frac{1800}{36}
\][/tex]

- Determine the percentage increase:

[tex]\[
\text{Percentage Increase} = \left( \frac{\text{New Mean} - \text{Original Mean}}{\text{Original Mean}} \right) \times 100
\][/tex]



Answer :

GinnyAnswer
Sure, let's go through the problem step-by-step:

### Step 1: Calculate the Mean for Discrete Data

The formula to calculate the mean for discrete data is:

[tex]\[ \text{Mean} (\bar{x}) = \frac{\sum fx}{\text{Total number of observations (n)}} \][/tex]

Where:
- [tex]\( \sum fx \)[/tex] is the sum of the product of frequency (f) and the variable (x).
- [tex]\( n \)[/tex] is the total number of observations.

Given:
- [tex]\( \sum fx = 1620 \)[/tex]
- Number of observations ([tex]\( n \)[/tex]) = 36

Plugging in the values:

[tex]\[ \text{Mean} (\bar{x}) = \frac{1620}{36} = 45.0 \][/tex]

The mean of the original data is 45.0.

### Step 2: Calculate the New Mean After 6 Observations are Removed

If 6 observations are removed, we need to adjust the total number of observations and the sum of fx.

Number of observations removed = 6

New total number of observations = [tex]\( 36 - 6 = 30 \)[/tex]

To find the new sum of [tex]\( fx \)[/tex]:
- The 6 removed observations have the same mean as the original data which is 45.0 each.
- So, the total [tex]\( fx \)[/tex] for these 6 observations is [tex]\( 6 \times 45.0 = 270 \)[/tex].

New sum of [tex]\( fx \)[/tex] = [tex]\( 1620 - 270 = 1350 \)[/tex]

Now, the new mean is:

[tex]\[ \text{New Mean} = \frac{1350}{30} = 45.0 \][/tex]

### Step 3: Calculate the Percentage Increase in the Mean After Adding 180 to the Original Σfx

If 180 is added to the original sum of [tex]\( fx \)[/tex]:
- [tex]\( \sum fx \)[/tex] with addition = [tex]\( 1620 + 180 = 1800 \)[/tex]

The new mean after this addition:

[tex]\[ \text{New Mean with Addition} = \frac{1800}{36} = 50.0 \][/tex]

To find the percentage increase in the mean:

[tex]\[ \text{Percentage Increase} = \left( \frac{\text{New Mean with Addition} - \text{Original Mean}}{\text{Original Mean}} \right) \times 100 \][/tex]

Using the values:

[tex]\[ \text{Percentage Increase} = \left( \frac{50.0 - 45.0}{45.0} \right) \times 100 = \frac{5.0}{45.0} \times 100 \approx 11.111 \][/tex]

So, the mean increases by approximately 11.11% when 180 is added to the original sum of [tex]\( fx \)[/tex].

### Summary of Results

- The original mean is 45.0.
- The new mean after removing 6 observations is 45.0.
- The new mean after adding 180 to the original [tex]\( \sum fx \)[/tex] is 50.0.
- The percentage increase in the mean after adding 180 to the original [tex]\( \sum fx \)[/tex] is approximately 11.11%.

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