In 1999 the stock market took big swings up and down. A survey of 1 comma 007 adult investors asked how often they tracked their portfolio. The table shows the investor responses. What is the probability that an adult investor tracks his or her portfolio​ daily?

Question

Start 6 By 2 Table 1st Row 1st Column How frequently question mark 2nd Column Response 2nd Row 1st Column Daily 2nd Column 224 3rd Row 1st Column Weekly 2nd Column 281 4st Row 1st Column Monthly 2nd Column 288 5st Row 1st Column Couple times a year 2nd Column 144 6st Row 1st Column Don't track 2nd Column 70 EndTable

Answer 1

To find the probability that an adult investor tracks their portfolio daily, you first need to determine the total number of respondents and the number of respondents who track their portfolio daily.

From the data provided:

• Total respondents = 1,007
• Respondents who track their portfolio daily = 224

The probability \( P \) that an adult investor tracks their portfolio daily is calculated using the formula:

\[ P(\text{Daily}) = \frac{\text{Number of Daily Trackers}}{\text{Total Number of Respondents}} \]

Substituting the values:

\[ P(\text{Daily}) = \frac{224}{1007} \]

Now, calculating this value:

\[ P(\text{Daily}) \approx 0.222 \]

So, the probability that an adult investor tracks his or her portfolio daily is approximately 0.222, or 22.2% when expressed as a percentage.