Module 1 challenge :Process Data from Dirty to Clean (Google Data Analytics Professional Certificate) Answers 2025

Question 1

Fill in the blank: If a test is statistically _____, the results are less likely to be due to random chance and more likely due to a real difference.

✅ Significant
❌ Precise
❌ Repeatable
❌ Connected

Explanation:
A statistically significant result means the likelihood that the result occurred by chance is low — usually below a predefined threshold (e.g., p < 0.05).

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Question 2

Conversion formula off by a factor of 10 — what data integrity problem is this?

✅ Manipulation
❌ Gathering
❌ Transfer
❌ Replication

Explanation:
When data is altered incorrectly (even unintentionally) during processing or transformation, it’s a manipulation error — causing corrupted or inaccurate results.

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Question 3

Survey result = 65% ± 3% margin of error. What is the range of true response?

✅ 62–68%
❌ 68–71%
❌ 60–63%
❌ 65–68%

Explanation:
Margin of error gives a confidence interval:
65% ± 3% = 62% to 68%, which estimates the true population response.

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Question 4

Principal surveys only first- and second-year students. What will result?

✅ Sampling bias
❌ Geographically limited sampling
❌ Random sampling
❌ Unbiased sampling

Explanation:
By excluding older students, the sample is not representative of the full population — creating sampling bias.

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Question 5

Fill in the blank: A data analyst uses _____ to determine whether an experiment or survey has meaningful results.

✅ Hypothesis testing
❌ Trial and error
❌ Approximation
❌ Estimation

Explanation:
Hypothesis testing is the formal method to determine if differences or relationships in data are statistically meaningful or due to chance.

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Question 6

What must be known to calculate margin of error (besides sample size and confidence level)?

✅ Population size
❌ Distribution
❌ Correlation
❌ Testing methodology

Explanation:
The population size affects how representative the sample is — it’s an essential factor in calculating the margin of error accurately.

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Question 7

Accidentally unplugging the USB before transfer completion — what problem is this?

✅ Transfer
❌ Replication
❌ Manipulation
❌ Cleaning

Explanation:
When data becomes incomplete or corrupted during movement from one system to another, that’s a transfer error.

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Question 8

Which statements describe sample size, population, and confidence level accurately?

✅ Using sample size makes it possible to get enough information from a small group within a population to draw conclusions about the whole.
✅ The goal of random sampling is to ensure every possible type of sample has an equal chance of being chosen.
✅ For effective outcomes, a data professional aims for a high confidence level.
❌ A confidence level of 75% is ideal.

Explanation:

• Random sampling avoids bias.

• Higher confidence levels (90%, 95%, 99%) are preferred for reliable conclusions.

• 75% is too low for most industries.

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🧾 Summary Table

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