Question

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% 5%

Slightly Optimistic 11% 18%

Slightly Pessimistic 25% 22%

Pessimistic 57% 55%

Step 6 of 10 : Find the value of the test statistic. Round your answer to three decimal places. Answer How to enter your answer

Step 7 of 10: Find the degrees of freedom associated with the test statistic for this problem

Step 8 of 10: Find the critical value of the test at the 0.025 level of significance. Round your answer to three decimal places.

Answer #1

step 6)

Applying chi square test of independence: |

Expected |
E_{i}=row total*column
total/grand total |
1st | 2nd | Total |

Optimistic | 15.0 | 15.0 | 30 | |

Slightly Optimistic | 36.3 | 36.3 | 73 | |

Slightly Pessimistic | 58.8 | 58.8 | 118 | |

Pessimistic | 140.0 | 140.0 | 280 | |

total | 250 | 250 | 500 | |

chi
square χ^{2} |
=(O_{i}-E_{i})^{2}/E_{i} |
1st | 2nd | Total |

Optimistic | 0.417 | 0.417 | 0.8333 | |

Slightly Optimistic | 2.112 | 2.112 | 4.2241 | |

Slightly Pessimistic | 0.239 | 0.239 | 0.4787 | |

Pessimistic | 0.045 | 0.045 | 0.0893 | |

total | 2.8127 | 2.8127 | 5.6255 | |

test statistic
X^{2}= |
5.625 |

step 7 :

degree of freedom(df) =(rows-1)*(columns-1)= |
3 |

step 8:

for 3 df and 0.025 level,critical value χ2= |
9.348 |

**fail to reject the null hypothesis**

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...

A psychologist conducted a survey of the attitude towards the
sustainability of American energy consumption with 230 randomly
selected individuals several years ago. The psychologist believes
that these attitudes have changed over time. To test this he
randomly selects 230 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 35%, 38% Slightly Optimistic 12%, 14%
Slightly Pessimistic...

A psychologist conducted a survey of the attitude towards the
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selected individuals several years ago. The psychologist believes
that these attitudes have changed over time. To test this he
randomly selects 380 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?
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1st Survey
2nd Survey
Optimistic
6%
1%
Slightly Optimistic
29%
30%
Slightly Pessimistic...

A psychologist conducted a survey of the attitude towards the
sustainability of American energy consumption with 380380 randomly
selected individuals several years ago. The psychologist believes
that these attitudes have changed over time. To test this he
randomly selects 380380 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 0.23 0.16
Slightly Optimistic 0.17 0.19
Slightly Pessimistic ...

A psychologist conducted a survey of the attitude towards the
sustainability of American energy consumption with 380 randomly
selected individuals several years ago. The psychologist believes
that these attitudes have changed over time. To test this he
randomly selects 380 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 0.23 0.16 Slightly Optimistic 0.17
0.19 Slightly Pessimistic...

A telephone company claims that the service calls which they
receive are equally distributed among the five working days of the
week. A survey of 110 randomly selected service calls was
conducted. Is there enough evidence to refute the telephone
company's claim that the number of service calls does not change
from day-to-day?
Days of the Week
Mon
Tue
Wed
Thu
Fri
Number of Calls
26
22
19
24
19
Copy Data
Step 1 of 10:
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