Under which of the following circumstances should the null hypothesis be accepted when a
= 0.05?
Correct Answer:
C
The null hypothesis should be accepted when the p-value is greater than the alpha level, which is the significance level of the test. The p-value is the probability of obtaining a test statistic at least as extreme as the one observed in the sample, assuming that the null hypothesis is true. The alpha level is the probability of rejecting the null hypothesis when it is true, which is also known as a type I error12.
In this case, the alpha level is 0.05, which means that there is a 5% chance of rejecting the null hypothesis when it is true. Therefore, to reject the null hypothesis, the p-value must be less than or equal to 0.05, which indicates that the test statistic is very unlikely to occur by chance under the null hypothesis. Conversely, to accept the null hypothesis, the p-value must be greater than 0.05, which indicates that the test statistic is not very unlikely to occur by chance under the null hypothesis.
Among the four options, only option D has a p-value that is greater than 0.05 (p = 0.06). Therefore, option D is the correct answer. When p = 0.06, it means that there is a 6% chance of obtaining a test statistic at least as extreme as the one observed in the sample, assuming that the null hypothesis is true. This probability is not very low, and therefore does not provide enough evidence to reject the null hypothesis.
A database administrator needs to ensure only approved users can access specific database tables to perform financial functions. Which of the following is the best access control method for the administrator to use?
Correct Answer:
A
A recurring event is being stored in two databases that are housed in different geographical locations. A data analyst notices the event is being logged three hours earlier in one database than in the other database. Which of the following is the MOST likely cause of the issue?
Correct Answer:
C
The most likely cause of the issue is that the databases are recording the event in different time zones. For example, if one database is in New York and the other database is in Los Angeles, there is a three-hour difference between them. Therefore, an event that occurs at 12:00 PM in New York would be recorded as 9:00 AM in Los Angeles. To avoid this issue, the databases should either use a common time zone or convert the timestamps to a standard format. Therefore, option C is correct.
Option A is incorrect because the data analyst is not querying the databases incorrectly, but rather observing a discrepancy in the timestamps.
Option B is incorrect because the databases are recording the same event, but with different timestamps.
Option D is incorrect because the second database is not logging incorrectly, but rather using a different time zone.
Which of the following are reasons to create and maintain a data dictionary? (Choose two.)
Correct Answer:
AB
The reasons to create and maintain a data dictionary are to improve data acquisition and to remember specifics about data fields. A data dictionary is a document or a database that describes the structure, meaning, and usage of the data elements in a data source or a database. A data dictionary can help to improve data acquisition by providing clear and consistent definitions, rules, and standards for the data collection process. A data dictionary can also help to remember specifics about data fields by providing information such as data type, format, length, range, default value, constraints, relationships, etc. The other options are not reasons to create and maintain a data dictionary, as they are related to other aspects of data management or security. A data dictionary does not specify user groups for databases, as this is a function of access control or authorization. A data dictionary does not provide continuity through personnel turnover, as this is a function of documentation or knowledge transfer. A data dictionary does not confine breaches of PHI data, as this is a function of encryption or anonymization. A data dictionary does not reduce processing power requirements, as this is a function of optimization or compression. Reference: [What is a Data Dictionary? - DataCamp]
A data analyst needs to create a master file that includes customer information from the tables below:
Given the three tables above, the analyst wants to filter down the information prior to joining it together. In which of the following orders should this data manipulation bo approached for the most efficient result?
Correct Answer:
B
For efficient data manipulation, the ideal order would be to first merge related tables to create a comprehensive set of records, then deduplicate to remove any redundant information. Lastly, appending additional data, such as from another source or table, ensures that all relevant data is included without redundancy before the final analysis. This order prevents unnecessary duplication of effort, such as deduplicating both before and after appending, which would be less efficient.
In the context of the tables provided, merging would likely involve combining customer information from the online and in-store transaction tables with the customer table. Deduplication would remove any redundant customer records that may exist across these tables. Finally, appending would involve adding any additional transaction records to the master file, ensuring a complete dataset for analysis.