A psychologist conducted a survey of the attitude towards the sustainability of American energy consumption with 250 randomly selected individuals several years ago. The psychologist believes that these attitudes have changed over time. To test this he randomly selects 250 individuals and asks them the same questions. Can the psychologist confirm his theory that the attitudes have changed from the first survey to the second survey?
| Attitude | 1st Survey | 2nd Survey |
|---|---|---|
| Optimistic | 7% | 6% |
| Slightly Optimistic | 9% | 6% |
| Slightly Pessimistic | 31% | 37% |
| Pessimistic | 53% | 51% |
Step 4 of 10: Find the expected value for the number of respondents who are optimistic. Round your answer to two decimal places.
As we are testing here whether the attitudes have changed from the first survey to the second survey, therefore we would be using the survey 1 percentages to get the expected frequencies here.
Therefore for a total frequency of 250, the expected number of respondents who are optimistic is computed here as:
= Percentage share for optimistic from 1st survey * 250
= 0.07*250
= 17.5
therefore 17.5 is the required expected value here.
A psychologist conducted a survey of the attitude towards the sustainability of American energy consumption with...
A psychologist conducted a survey of the attitude towards the sustainability of American energy consumption with 370 randomly selected individuals several years ago. The psychologist believes that these attitudes have changed over time. To test this he randomly selects 370 individuals and asks them the same questions. Can the psychologist confirm his theory that the attitudes have changed from the first survey to the second survey? Attitude 1st Survey 2nd Survey Optimistic 7% 11% Slightly Optimistic 28% 24% Slightly Pessimistic...
A psychologist conducted a survey of the attitude towards the sustainability of American energy consumption with 370 randomly selected individuals several years ago. The psychologist believes that these attitudes have changed over time. To test this he randomly selects 370 individuals and asks them the same questions. Can the psychologist confirm his theory that the attitudes have changed from the first survey to the second survey? Attitude 1st Survey 2nd Survey Optimistic 7% 11% Slightly Optimistic 28% 24% Slightly Pessimistic...
A psychologist conducted a survey of the attitude towards the sustainability of American energy consumption with 370 randomly selected individuals several years ago. The psychologist believes that these attitudes have changed over time. To test this he randomly selects 370 individuals and asks them the same questions. Can the psychologist confirm his theory that the attitudes have changed from the first survey to the second survey? Attitude 1st Survey 2nd Survey Optimistic 8% 3% Slightly Optimistic 26% 30% Slightly Pessimistic...
A psychologist conducted a survey of the attitude towards the sustainability of American energy consumption with 250 randomly selected individuals several years ago. The psychologist believes that these attitudes have changed over time. To test this he randomly selects 250 individuals and asks them the same questions. Can the psychologist confirm his theory that the attitudes have changed from the first survey to the second survey? Attitude 1st Survey 2nd Survey Optimistic 6% 13% Slightly Optimistic 12% 17% Slightly Pessimistic...